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DWIDP Bulletin January 2014 Series XIV 29DWIDP Bulletin

People's Embankment Program, Karnali River, Patabhar-9, Bardiya

Government of Nepal

Ministry of Irrigation

Department of Water Induced Disaster Prevention(DWIDP)

January 2014 Series XIV

DWIDP Bulletin January 2014 Series XIV30

PEP Field Offi ce No. 4, Chitwan / Narayani River Training Works in, Chitwan & Nawalparasi

Construc on of Embankment,Stud and Bio- Engineering work

River Bank Protec on Work, Sarlahi People's Embankment Program, Mahakali River

River Bank Protec on Work using Sand Bags & Bamboo Pilling

Public Awareness Seminar, Udaypur

DWIDP Bulletin January 2014 Series XIV

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Year

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3/20

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Advisory Board

Kamal Prasad RegmiDirector General

Gauri Shanker BassiDeputy Director GeneralDisaster Mitigation Division

Narendra Bahadur LamaDeputy Director GeneralPlanning, Program and Foreign Coordination Division

_____________________

Chief EditorPradeep Kumar ManandharSenior Divisional Engineer

EditorKhila Nath DahalSenior Divisional Hydrogeologist

Sundar Prasad SharmaSenior Soil Conservation Officer

Executive EditorKomal B. DhakalEngineer

Manju SharmaSociologist

Published by

Government of Nepal

Ministry of IrrigationDepartment of Water Induced Disaster Prevention

(DWIDP)


DWIDP Bulletin

Cover Photo: Percupine works at Holiya, Banke

Government of Nepal

Ministry of Irrigation

Department of Water Induced Disaster Prevention(DWIDP)

www.dwidp.gov.np

Editorial

To address the water induced disaster in the country Disaster Preven on Technical Centre (DPTC) was established in October 1991 with the technical and fi nical support from Japan Interna onal Coopera on Agency (JICA). This technical centre was an inter-disciplinary ins tute consis ng experts from diff erent government organiza on and focusing on all aspects of disaster preparedness.

To ins tu onalize this organiza on the technical centre was converted into the department - Department of Water Induced Disaster Preven on (DWIDP) under the then Ministry of Water Resources on February 2000 to work as focal agency for water induced disaster management in Nepal. Overall goal of DWIDP is to contribute to achieving the na onal goal of poverty allevia on through minimizing human casual es and damages of infrastructures due to water induced disasters by the appropriate management and conserva on of rivers and river basins of Nepal. Its tasks involve i) technology development work, ii) Training, study and informa on work, and iii) Structural disaster mi ga on work. In the process of strengthening the DWIDP on January 2002 River Training Division from the Department of Irriga on (DoI) was merged with this department. Then the organiza on was structured with two major divisions and six sec ons at the centre and seven division offi ces and fi ve sub-divisions covering the 75 administra ve districts of the country. Moreover, seven fi eld offi ces operated under the People's Embankment Program (PEP) to look a er river control ac vi es related to 14 specifi c rivers in the tarai. The structure of the departmental head quarters shows its origins, with one division covering the former DPTC ac vi es (e.g. technology development, training) and the other covering the former DoI's river engineering division tasks.

To cope with the changes in the development ac vi es, address the demands of the na on on water induced disaster mi ga on works, adapta on of innova ve and appropriate technologies the exis ng organiza on structure of DWIDP has been restructured. The new organiza on has been structured with three major divisions and 18 sec ons at the centre but there has been no change in the number of divisions, sub-divisions and fi eld offi ces at the district/project level. The organiza on structure in the centre may overcome the short comings of the previous one and will boost the ac vi es of the department for be er ins tu onal development and effi cient and eff ec ve delivery of its services. The three divisions and the sec ons within the divisions are categorized so as to enhance the ac vi es of the division.

Under the Planning, Program and Foreign Co-ordina on Division there are Planning and Program Sec on, Monitoring and Evalua on Sec on, Foreign Co-ordina on Sec on, Study and Research Sec on and Peoples' Embankment Program Sec on. These sec ons will co-ordinate the diff erent line ministries, sec ons/offi ces of the department, stakeholders and the aff ected benefi ciaries in planning and programming the short and long term plans, prepare project reports for loan/grant assistance from the donor agencies and eff ec ve execu on of the Peoples' Embankment Program. In the River Training Division there are River Training Sec on, Mechanical and Electrical Management Sec on and Emergency and Early Warning Management Sec on. The sec ons within this division will supervise the ongoing river training ac vi es and monitor its progress, mobilize and manage the emergency response opera on on water induced disasters along with early warning measures. Similarly, under the Disaster Mi ga on Division there are Landslide Management Sec on, Watershed Management Sec on, Training and Informa on Sec on, Technology Development Sec on, Bas -tar Management Sec on, Disaster Management and Environment Sec on. These sec ons will give con nuity to the former DPTC ac vi es along with manage landslide mi ga on measures, watershed management and implement measures to protect towns and agricultural lands (bas -tar) in the foothills along the rivers banks.

The Deputy Director Generals will be in charge of the divisions and the sec ons will be under the senior divisional engineer/engineering geologist/hydro-geologist. At the district/project level all the divisions and sub-divisions will be headed by the Senior Divisional Engineers instead of Engineers in the sub-divisional offi ces as per the previous organiza on structure. By this amendment the technical man-power of the divisions can increased to cope with the present issue on insuffi cient technical manpower to supervise the construc on ac vi es.

Finally in overall, it is expected that the amendment of the organiza on structure will enhance the ac vi es of the department and its divisional offi ces in eff ec ve delivery of its services.

Table of Contents• Events/Activities:

• Check Dam – A Hydrological Technique to Control Concentrated Flow Erosion

• Monsoon 2013 Associated with Severe Cyclonic Storm “Phailin” in Nepal

• An Introduction of Bamboo Porcupine Spur

• June 17, 2013 Flood and the Master Plan of Mahakali Rehabilitation Works, Darchula

• Glossary of Disaster Terms

• Standards, Norms and Criteria: Hazard Categorization and Defi nition

Janurary 2013 Series XIV

Photographs of Cover PicturePeople's Embankment Program, Karnali, River Patabhar-9, Bardiya

ntion

DWIDP Bulletin January 2014 Series XIV 3

Events/Activities:

Public Awareness SeminarsHaving with following expected outcomes DWIDP conducted Seminar for public awarness in Udayapur District from 12-13 Kartik 2070 (Oct 29-30, 2013).Expected outcomes Rapport build-up among service providers and receivers of water induced disaster management, Make familiar with the available services in the district on disaster mitigation activities, Enhanced technical, behavioral and social knowledge on water induced disaster risk reduction Establishment of mutual goal and coordination among the line agencies and communities.

In the Seminar there were had 64 participants from the member of District Natural Disaster Relief Committee, Red Cross Society, school teacher, social worker, civil society, women social mobilizer, VDC secretaries, local NGO/CBO and local media. The general objective of the program is to mitigate the disaster through non structural mitigation measure. The specifi c objectives of the seminar were: To bring together all the related organizations working in disaster fi elds to manage and mitigate water induced disasters. To increase awareness level among local people, district level line agencies towards causes and risks of water induced disaster. To bring common solution in raised-issues To work in coordinated and collaborative way to reduce water induced disaster To provide technical knowledge on water induced disaster to the stakeholders, community leaders, social workers and teachers. To make familiar with the existing status and opportunities in the fi eld of disaster management, mitigation and reduction that

provided by the different agencies in the district. to review the needs and demands of the community on water induced disaster mitigation. to rank the problems on the priority

basis.

21st Advanced Course TrainingDWIDP has been conducting an Advance Course Training (ACT) and a General Course Training (GCT) for knowledge and skill development of engineers and sub-engineers of the department and line agencies annually. These trainings will enhance the capacity of the engineering professionals and technicians to execute the required task on disaster reduction and mitigation. These types of training are conducted for thirty plus working days and awarded certifi cate to the participants which will be useful to fulfi ll the promotion criteria for the Civil Service. So far, 20 events of Advance Course Training and 23 events of General Course Training have already been conducted. Following the past years, the 21st ACT is now ongoing which will be fi nished on 03rd of Magh 2070. The general objective of the training is to enhance knowledge and skill of the technical personnel working in the fi eld of water induced disaster

The specifi c objectives of the program are as follows: to provide technical and theoretical knowledge about material testing, geology, hydrology, landslide, SABO works, river

training works, watershed management, GIS, remote sensing and bio-engineering works with reference to water induced disaster

to familiarize disaster management in Nepal, process and procedures of procurement of works and services, environmental impact assessment and report writing techniques regarding to water induced disaster management and mitigation

to make fi eld study of the different project site(s) of DWIDP, for case study to produce report on WID mitigation measures.

Retirement

Director General Pradip Raj Pandey has retired due to age factor on Poush 30, 2070. The department honors his contributions to the department and wish him for his bright future and prosperous life.

New Appointment

Mr. Kamal Prasad Regmi, Joint Secretary of Ministry of Irrigation has been appointed as the 11th Director General of DWIDP from Magh 14, 2070. He was also the Director General of DWIDP from 2068-2-23 to 2069-1-15.


RestructuringTo fulfi ll the increasing role and responsibility in effective and effi cient way the organization of the department has been restructured.

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Abstract of Human Resource (Staffi ng) in Department and Division, Sub-division Offi ces

S.N. Post Class Service Group Subgroup DepartmentDepartment

(PIG)*Division Offi ces

(7 Nos)Sub-Division

Offi ces (5 Nos)Total

1 Director General Gaz. I Engineering 1 1

2 Deputy Director General Gaz. I Engineering Civil Irriga on 2 2

3 Deputy Director General Gaz. I Engineering Agri-irriga on 1 1

4 Senior Divisional Hydro-geologist Gaz. II Engineering Geology Hydro-geology 2 2

5 Senior Divisional Engineer (agri) Gaz. II Engineering Agri-irriga on 1 1 2

6Senior Divisional Engineering Geologist

Gaz. II Engineering Geology Engineering geology 1 1

7 Senior Divisional Engineer (civil) Gaz. II Engineering Civil Irriga on 10 10 7 5 32

8 Senior Divisional Engineer (mech) Gaz. II Engineering Mechanical Cons. Mch. Mntnc.** 1 1

9 Under Secretary (account) Gaz. II Adminstra on Account 1 1

10 Account Offi cer Gaz. III Adminstra on Account 1 7 2 10

11 Sec on Offi cer Gaz. III Adminstra on General admin. 1 1

12 Legal Offi cer Gaz. III Judicial Legal 1 1

13 Engineer (civil) Gaz. III Engineering Civil Irriga on 10 40 88 31 169

14 Engineer (agri) Gaz. III Engineering Agri-irriga on 2 2 4

15 Engineering Geologist Gaz. III Engineering Geology Engineering Geology 1 1

16 Engineer (hydrology) Gaz. III Engineering Civil Hydrology 1 1 2

17 Engineer (hydropower) Gaz. III Engineering Civil Hydropower 1 1

18 Engineer (mechnical) Gaz. III Engineering Mechanical Cons. Mch. Mntnc.** 1 1 2

19 Engineer (highway) Gaz. III Engineering Civil Highway 1 1

20 Sociologist Gaz. III Miscellaneous Miscellaneous 1 1

21 Sub-engineer Gaz. III Engineering Civil Irriga on 6 1 2 12 21

22 Sub-engineer Gaz. III Engineering Civil Highway 1 1

23 Accountant Non-Gaz.I Adminstra on Account 1 6 2 9

24 Nayab Subba Non-Gaz.I Adminstra on General admin. 3 4 2 9

25 Senior Mechanic Non-Gaz.I Engineering Mechanical Cons. Mch. Mntnc.** 1 2 3

26 Computer Operator Non-Gaz.I Miscellanous Miscellanous 2 2

27 Typist Na. Su. Non-Gaz.I Adminstra on General admin. 1 1

28 Lab boy/Assistant Non-Gaz.I Miscellaneous Miscellanous 1 1

29 Senior Associa on Organizer` Non-Gaz.I Engineering Agriculture 2 2

30 Kharidar Non-Gaz.II Adminstra on General admin. 1 5 3 9

31 Assistant Accountant Non-Gaz.II Adminstra on Account 2 2

32 A.O. Non-Gaz.II Engineering Agriculture 1 1

33 Driver Class less Engineering Mechanical 1 1

34 Offi ce Helper Class less Adminstra on General admin. 5 30 9 44

Grand Total 62 56 155 69 342

* PIG = Project Implemen ng Group** Cons.Mch.Mntnc. = Construc on Machinery Maintenance


Check Dam –A Hydrological Technique to Control Concentrated Flow Erosion

Lal Chand PradhanSenior Consulting Engineer/

Former DDG, DWIDP

1. INTRODUCTION

In a sloping topography, concentrated fl ow of water erodes the soil mantle deepening its course forming gullies. A check dam is a hydrological low dam structure constructed across a gully or a channel or any other water course like a torrent to prevent and protect the water course from deepening by decreasing the velocity of water fl ow and the erosive power of runoff. It promotes the deposition of eroded materials, minimizes or stops channel and lateral erosion, and hence it stabilizes a gully or a watercourse.

2. FUNCTIONS

Check dams are designed and constructed to meet the following functions: i) reduce the velocity of water, ii) raise the bed level and reduce the slopes in a gully by silting up and trapping the silt from going downstream, and support the unstable side slopes and prevent channel and lateral erosion, iii) reduce the water depth by widening the gully or channel bed, and promote water percolation in the soil, and conserve water for plant growth for stabilizing banks.

Fig.1: Check dams in Fewa watershed

Fig.2: Check dams in Lankuridanda, Dolakha (Photo: L.C.Pradhan)


3. TYPES OF CHECKDAM General Characteristics Advantages Disadvantages

Brushwood Check dam(Fig.3)

Made of wooden poles and brush, Least permanent of

all the other types, Suitable for small gullies of 1

to 2 meters in depth, Low cost, where materials are

locally available.

Simple, Use local materials, Low cost, After the roots and

shoots come out, they can form a long term barrier.

Takes long time for the check dams to develop the roots and get established

Loose stone Check dam(Fig.4)

Made of loose stones or rocks, Stability and strength depend

on the size of rocks and quality of the construction, and Commonly used in the gully

control works, where stones are abundantly available

Use local materials Simple Low cost

(where stones are abundantly available)

If not made properly and sizeable stones are not used, the stones will be moved by the large water fl ow, and they may be quickly damaged.

Boulder Check dam(Fig. 5)

Made of big boulders or rocks. stability and strength depend

on the size of the boulders or rocks and quality of the construction. Commonly used in the gully

control works, where boulders or rocks are abundantly available.

Use locally available materials, such as boulders,

Simple Low cost (where

boulders are a b u n d a n t l y available)

If properly made, are almost like a permanent structure and durable

Transportation of the big boulders is diffi cult(especially, if not located upslope of the site) Large voids, if not properly fi lled up

in the dam, may create water jets, which could be destructive if directed towards banks

Gabion Check dam(Fig. 6)

Made with wire crates (Gabion Boxes) of different sizes fi lled with stones, Flexible, Preferred where big boulders

are not available

Flexible and permeable

Suitable, where land mass is unstable

E c o n o m i c a l compared to other solid structures

Costlier than loose stone or boulder structures Gabion has to be brought

from outside or imported, not locally available; so the community has to bear the cost of the gabion Need skilled labor for their

construction

Masonry Check dam(Fig. 7)

Made of cement masonry or concrete Not commonly used in

ordinary locations, except to protect important infrastructures such as road, building etc

Permanent and solid structure

Have aesthetic look

Costly Materials (cement, rods)

are not locally available Need more engineering design,

and skilled labor for the construction.


4. DESIGN CONSIDERATIONS

4.1 Site Selection

Following considerations need to be taken for the selection of sites for the construction of check dams: i) the site should be wide enough to limit specifi c runoff. To accommodate higher run off, it is necessary to select a wide enough place to limit the specifi c run off and the scour depth. The spillway has to be large enough with adequate free board to take expected peak run off, otherwise the side foundation of the check dam will be washed out and the check dam will be by- passed by the runoff and destroyed. ii) A check dam should be made at a straight and fi rm stream bed and bank. It should not be made on a curve and junction of gullies or streams, and just below the gully junction. iii) Stable site should be located for the base foundation and side foundation. It is necessary to build the fi rst check dam on good foundation base rock as it affects the foundation of the rest of the check dam above. iv) The selection of the site is also restricted by the height of the structure. If the elevation difference between two successive sites is too high, one or more sites have to be selected in between so that the structure height will fulfi ll the conditions.

For gullies which are part of other natural drainage system, only check dams with a long life-span are suitable (Agpaoa, A., et al, 1976).

4.2 Spacing of Check Dams

The spacing of the check dams should be so placed that the line joining the top of the lower check dam and the bottom of the successive upper check dam gives the gradient. This gradient for the kind of soil in the gully bed or stream bed will give a non-erosive velocity of fl ow. This gradient is known as the compensation gradient. For general practice, the compensation gradient is taken as 3 to 5 per cent slope.

Horizontal distance between successive check dams is given by the relation:

d = h * 100/ (So- Se),

Where, d = spacing between two successive check dams, h = height of the check dam up to the notch, So= existing slope of bed in %, Se= stabilizing slope of bed in% (in general it is 3 – 5 %).

4.3 Number of Check dams

It is calculated from the following formula:

Number of check dams = (a – b)/ H,

Where, a = the total vertical distance between the fi rst and the last check dam in that portion of the gully or torrent, b = Se * d’ / 100 = the total vertical distance calculated according to the compensation gradient for that portion of the gully, d’ = the horizontal distance between the fi rst and the last check dam in that portion of the gully or torrent, H = average height of the check dams.

4.4 Hydrological Design

Run off Estimation

There are various methods or formulas to estimate the runoff rate. However, the rational formula is a simple method and uses the watershed area, the rainfall intensity, and a factor called a dimensionless coeffi cient.

The peak rate of runoff is calculated by using the following Rational Formula:

Q = C * Itc * A / 360

Where,Q = The rate of runoff in cubic meter per second or cumecs, C = Dimensionless run off coeffi cient; Itc = The rainfall intensity, that is the rate of rainfall in mm per hour for the designed frequency for a duration equal to the time of concentration, tc ; A = Watershed area in hectares.

4.5 Hydraulic Design

4.5.1 Notch Design

The notch of the check dam, i.e. the spillway section, is designed by considering that the spillway has to accommodate the peak runoff, otherwise the side foundation of the check dam will be washed out and the check dam will be destroyed.

Figure 8: Front view of a check dam

Notch/weir or spillway can be designed by using the following formula:


Rectangular Notch: Francis’s Formula -

Q = 1.84 * Bsp * Hsp1.5

Where, Q = Peak runoff in cumecs, Bsp = Length of the Notch in meters, Hsp = Height of Notch in meters.

Specifi c runoff, q = Q/ Bsp cumecs /meter

For a trapezoidal notch, length of the notch is calculated as the average of top and bottom lengths of the notch.

4.5.2 Foundation Depth

The foundations are given to a check dam to anchor it in the ground for its stability so that it does not give away or over turn when the run off or peak fl ows occur and the dam is silted up. The following considerations need to be taken while designing and constructing the foundation of a check dam: i) the depth of foundation must be taken below the scour level, ii) in the erodible strata if Ds is the anticipated maximum depth of scour below the designed highest fl ood level including that on account of possible concentration of fl ow, the minimum depth of foundation below the highest fl ood level should be taken as 1.33 * Ds, iii) the scour depth is not to be taken from the present bed level but from one to be expected in the future after siltation of the lower check dam and after the establishment of new bed gradient due to the reduced bed load after the erosion control, iv) take a 1.0 m foundation as a rule of thumb.

Figure 9: Foundation depth of a check dam (B. Hiller, 1979).

Scour Depth

Scour occurs when the bed velocity of the stream exceeds the velocity, which can move the particles of the bed material. Velocity varies with the gradient, the hydraulic depth and the characteristics of the bed and the banks. When the velocity is retarded, silt is dropped; and when the velocity is increased, silt is picked up. Scour is worse when the fl ow is falling. It depends more on the water depth than on the gradient. A stream or river has to adjust its velocity to what its bed and banks can stand by changing its section.

Figure 10: Scour depth in a check dam (B.Hiller, 1979)

Q = runoff; H = height of energy line; q = specifi c runoff; hcr = critical height; h = fall height of check dam; hw = water cushion height; hs = scour water depth (Ds); hsh = scourable depth; ls = scour hole length; bsh = breadth of scour hole; hf = height of foundation; ( Units in m, sec)

The scouring action of the current is not uniform and it is all along the bed width; and scouring is deeper at the obstructions and also at bends than normal. Therefore, the maximum scour depth has to be determined.

Scour Depth Estimation

i) Normal scour depth is calculated using Schocklitch’s Formula:

Scour Depth, DS = (4.75 * h 0.2* q 0.57) /dm 0.35

Where, DS = Scour depth in meter below water level; h = water level difference in meter above and below the check dam, q = run off in cubic meters /meter width in the spillway; dm = Grain diameter in mm which divides bed material in a way that 90 % is smaller than dm.

ii) Breadth of scour hole is calculated as: Breadth of Scour Hole or Apron = 1.5 * Length of the Notch

iii) Length of scour hole is calculated as: Length of Scour Hole or the Apron = 4 * (0.467 * q2/3) 1.5 * h 0.5

Side Foundations: Giving side foundations of a check dam into the gully side slopes prevents the destructive fl ows of water around the dam and consequent scouring of the banks. Keying a check dam into the side slopes and bottom of the gully greatly enhances the stability of the structure, which is important where expected peak fl ow is large, and soils are highly erosive.

Apron: Apron must be installed on the gully bottom and protective works on the gully side slopes below the check dam, otherwise fl ows may undercut the structure from downstream and destroy it. The apron should be roughly level on its surface and go down about 0.3 m below the original bottom elevation (Burchard H. Heede, 1976).


4.6 Structural Design

Structural design involves the determination of the dimensions of the various components of the check dam, its strength and stability. The safety of the check dams is mostly endangered by scouring. Foundation depth and spillway size and shape have, therefore, to be selected taking scouring depth into consideration.

Check dams are designed for: i) Safety against overturning; ii) Safety against sliding; and iii) Safety against the bearing pressure on the foundation soil. Middle third rule should hold since common check dams are gravity check dams. Stability test for the check dam is carried out same as retaining wall.

5. CONSTRUCTION CONSIDERATIONS

General Construction Considerations

The following general construction considerations should be taken into account to get a satisfactory result from check dam construction (Hiller, 1979).

Construct check dams at the same time as the treatment of the upper watershed and adjacent side slopes (like plantation, diversion channel, retaining walls, trimming steep slopes).

Select the appropriate construction site, and design properly as per site condition.

Choose the best construction materials available nearby.

For loose stone or boulder check dams, make good dry masonry structures with big, well shaped, hard stones. Use the biggest and hardest stones for the spillway section and the foundations.

For gabion check dams stone size must be bigger than the mesh. Only dry masonry may be used with well shaped and hard stones. The gabions must be well and fi rmly tied fi rst to close the gabion box itself and second to fi x the gabion with its surroundings.

Gabions should not be exposed to fl owing or falling water especially if there is a bed load.

The foundation must be fi rmly based in the sub-soil and in the banks. The foundation depth depends on the quality of the soil and the rock.

The spillway section must take the peak runoff fl ow. Prevent water fl ow by-passing the check dam sides by

providing guide walls or wing walls. Plan the life span of the structures for longer period to

justify economically. Maintenance is as important as the construction itself.

6. MAINTENANCE AND REPAIR

General Maintenance

After the construction, maintenance of different types of check dams is very important to be followed for the stability, longevity and effectiveness of the structures. Structures which are not maintained well may have disastrous consequences by possible destructions. Maintenance of structural measures must be continued for at least two or more years after the treatment year.

Normally maintenance consists of the following aspects:

i) Inspections: Treated areas must be inspected at least once a year or more. A check up must be done before and after the monsoon. Basically all the check dam structures, watercourse (bed and bank erosion, obstacles etc.) and slope protection must be checked.

ii) Care of plantations and of watercourses:

- Drainage: Weeds should be removed and cleaned in ditches, and repair ditches.

- Slopes: Wherever necessary grass cutting or restoration of grass or plant cover should be done; it is to be checked for if there are any newly formed rills, gullies and slides developed with brushwood check dams and with other vegetative methods of slope stabilization.

- Water courses: Water courses should be cleaned of deposits, woods, branches, big stones etc. Erosion trends must be recognized and controlled immediately. Changes of water courses must be monitored and controlled.

Repair works: Check dam structure such as brushwood, loose stone, boulder, gabion or masonry check dam must be repaired timely once it gets damaged or worn out.

- Check dams have to be checked for the conditions of the spillway section, bed and bank foundations or damages to any structural part due to rotting, hitting or abrasion. Scouring damage above and below the structure and condition of the apron must be looked at.

- With these structures, every damaged part has to be repaired, changed or patched up. Scouring damage must be repaired by setting a better protection (big stones, gabions, masonry etc.).

- Rotting check dams (brushwood) are exchanged by removing the old one or


constructing a new one in front of the old one.

- Out washing of brushwood check dams must be restored and dead plants replaced.

Supplementary works: Normally at the fi rst attempt full success may not be gained in gully stabilization, especially in new constructions. Some additional structures may be necessary for bank protection or other works; and in such cases, supplementary structures should be constructed.

7. CAUSES OF FAILUREThe main causes of failures of check dams may be attributed to human as well as natural factors.

Human factors for failure of check dam may include inadequate design and construction considerations, which may be specifi ed as given below:

a. Faulty or inadequate design steps, specifi cations or process followed: incorrect spacing, incorrect effective heights, inadequate spill way section, less or no foundation depth, no provision or inadequate keying of foundation or sides of check dams, no provision of wing walls, no or inadequate apron;

b. Construction process not followed properly or faulty construction or low grade of construction materials used because of low knowledge, skill, experience, economy or mere negligence;

c. No or inadequate maintenance activities; no or very limited monitoring;

d. Deteriorating watershed conditions because of human interventions.

Natural factors for failure of check dam may include unexpected fl ow conditions and debris fl ow or mass movement because of cloudburst or high rainfall intensities more than that were considered in the design, natural disaster or phenomenon like earthquake, geological conditions, and tectonic movement beyond human control.

REFERENCES1. Agpaoa, A., et al (1976). Manual of Reforestation and

Erosion Control for the Philippines (Compiled by H. J. Weidelt), gtz, Eshborn.

2. Department of Water Induced Disaster Prevention, / Department of Civil Engineering, Insti tute of Engineering, TU , (2001) Water Induced Disaster Prevention Training Manual, Department of Water Induced Disaster Prevention, Lalitpur

3. Geyik, M. P , (1986),FAO Watershed Management Field Manual Gully control FAO Conservation Guide

13/2, FAO of the UN, Rome, 4. Gupta, S. K., K.G. Tejwani and H.N. Mathur (1975).

Soil and Water Conservation Research 1956 -71, Indian Council of Agricultural Research ,New Delhi

5. Hattinger, Hubert, ( 1976), Torrent Control in the Mountains With Reference to the Topics, FAO Conservation Guide – 2: Hydrological Techniques for Upstream Conservation, FAO, Rome.

6. Hiller, Bernhard, (1979). Manual Calculation of Check Dams, Department of Soil and Water Conservation/ Swiss Assistance for Technical Assistance, Kathmandu, Nepal.

7. Heede, Burchard H., (1976). Gully Development and Control: The Status of Our Knowledge, US Department of Agriculture, Forest Service, Colorado, USA

8. Heede, Burchard H , (1977). Gully Control Structures and Systems, FAO Conservation Guide – 1Guidelines for Watershed Management, FAO of the UN, Rome.

9. Michael, A.M. and T. P. Ojha (1966). Principles of Agricultural Engineering, Jain Brothers, Jodhpur.

10. Pradhan, Lal Chand, (1985). Design, Construction and Evaluation of Small Scale Structures for Controlling Concentrated Flow Erosion. M.S. Thesis, The University of Arizona, Tucson, Arizona,U.S.A.

11. Shah, Bashir Hussain , (1992). An Economic Approach to the Design of Erosion Control Structures Using Local Materials, Regional Watershed Project, UNDP: FAO of the UN, Kathmandu.

12. Soil Conservation and Watershed Management Measures and Low cost Techniques, Soil Conservation and Watershed Management Component (NARMSAP),( 2004). DSCWM, Kathmandu.

13. Soil Conservation and Watershed Component (NARMSAP) (2005). Training Hands out on Bio Engineering and Survey, Design and Estimation of Soil Conservation Activities, Department of Soil Conservation and Watershed Management, Kathmandu, Nepal.

14. Sthapit, Keshar Man, (1998). Teaching Material on Soil Conservation Engineering, Institute of Forestry/ International Tropical Timber Organization, Project PD: The Training and Manpower Development in Community Forestry Management, Pokhara, Nepal.

15. Schwab, Glen O., Richard K. Frevert, Talcott W. Edmisnster and Kenneth K. Barnes(1981), Soil and Conservation Engineering, John Wiley and Sons, New York.

16. United States Department of Agriculture Fores Service, (1969). Watershed Structural Measures Handbook, Washington

17. U.S. Department of Agriculture (1973). How to control Gully , Washington.


Monsoon 2013 Associated With Severe Cyclonic Storm “Phailin” In Nepal

Mani Ratna Shakya(Senior Meteorologist)

1. Introduction

Monsoon is the main source of rain for livelihood of human beings in a mountainous country like Nepal. The monsoon onsets in Nepal in the eastern part on 10 June, and withdraws completely from Nepal on 23 September. However, the monsoon prolongs for several days, sometimes, when it is affected by cyclone. It solicits unexpected natural disasters such as heavy rain with strong winds, fl oods etc. altering the activities of human lives reluctantly. In this context, the monsoon 2013 is an example in the history of Nepal that is extended by 22 days against the normal. The monsoon 2013 was withdrawn completely from Nepal on 19 October against the normal date 23 September. This has prolonged the monsoon 2013 in Nepal for 127 days. The normal monsoon day in Nepal is 105 days. This is the longest period of monsoon extended in Nepal after 25 years since 1989.The main reason behind the extension of the monsoon is the occurrence of severe cyclone named “Phailin” in the north of Andaman sea of Bay of Bengal in the middle of October.

Emerge of the event:The system was fi rst noted as a tropical depression on October 4, 2013 in west of Pnom Penh in Cambodia within the Gulf of Thailand. Over a few days, it moved westwards within an area of low to moderate vertical wind shear. It moved out of the Western Pacifi c Basin on October 6 and emerged into the Andaman Sea.

Visiting faculty, Department of Enviormental Science and Engineering,

Kathmandu University, Nepal

E-mail- [email protected]

The deep depression over north Andaman Sea intensifi ed into a cyclonic storm Phailin on October 9. It then moved slightly westwards, intensifi ed into a severe cyclonic storm in the forenoon and further intensifi ed into a very severe cyclonic storm at 06:00 UTC on 10 October 2013 extending into the coordinate of 15.00N and longitude 90.50E, about 800km southeast of Paradip, 850km east-southeast of Kalingapatnam, and 870 km east-southeast of Visakhapatnam (Fig.1)

Fig 1. Severe cyclonic Storm Phailin

The cyclone Phailin as intensifi ed rapidly as a very severe cyclonic storm on October 10, is equivalent to a category 1 hurricane on the Saffi r-Simpson hurricane wind scale (SSHWS). On October 11, the system became equivalent to a category 5 hurricane on the SSHWS before it started


to weaken during the next day as it approached the Indian state of Odisha. The storm track can be observed in Fig. 2.

The very severe cyclonic storm, Phailin crossed Odisha & adjoining north Andhra Pradesh coast near Gopalpur in Odisha around 1600 UTC of 12th October 2013. It subsequently weakened over land as a result of frictional forces, before it was last noted on October 14, as it degenerated into a well marked area of low pressure ( www.imd.gov.in).

Fig 2. Storm track of severe cyclonic storm Phailin 2013.source:(www.imd.gov.in).

The salient features of the storm:

a) Very cyclonic Storm Phailin is the most intense cyclone after Odisha Super Cyclone of 29th October 1999, that crossed India coast affecting different parts of South Asia.

b) There was rapid intensifi cation of the system from 10th to 11th October morning leading to an increase in wind speed from 45 knots to 115 knots.

c) At the time of landfall on 12th October, maximum sustained surface wind speed in association with the cyclone was about 115 knots (215 kmph) and estimated central pressure was 940 hPa with pressure drop of 66 hPa at the centre compared to surroundings.

d) It caused very heavy to extremely heavy rainfall over Odisha leading to fl oods, and strong gale wind leading to large scale structural damage and storm surge leading to coastal inundation over Odisha.

e) Based on post-cyclone survey report, maximum of storm surge of 2-2.5 meters above the astronomical tide has been estimated in the low lying areas of Ganjam district of Odisha in association with the cyclone and the in-land inundation of saline water extended up to about one kilometer from the coast.

Synoptic features associated with the cyclone:

The synoptic features associated with the cyclone explain clearly the alteration in weather with space and time. Hence, it is of great importance to know the feature of the cyclone in detail which is explained as below.

• A trough extending from eastern parts of Jammu & Kashmir to east-central Arabian Sea across Haryana, east Rajasthan and Gujarat region in mid-tropospheric level observed on October 4th.

• The trough extends from Nepal to east-central Arabian Sea across Uttar Pradesh, West Madhya Pradesh, Maharashtra and Konkan & Goa on 5th and became less marked on 6th.

• Another upper air cyclonic circulation laid over Assam & Meghalaya and neighbourhood extending upto 3.1 kms above mean sea level on 6th. It persisted over the same area on 7th and laid over Tripura & neighbourhood extending upto 3.1 kms above mean sea level on 8th. It laid over Bangladesh & adjoining north Bay of Bengal extending upto mid-tropospheric Levels on 9th.

• An off shore trough at mean sea level extending from south Maharashtra coast to Kerala coast on 6th and became less marked on 7th.

• An east-west trough extending from Assam & Meghalaya to Gujarat region across Jharkhand and Madhya Pradesh between 3.1 & 5.8 kms above mean sea level on 7th. It extending from Manipur to Gujarat region across Jharkhand and Madhya Pradesh on 8th, from north Andhra coast to south Gujarat region across Maharashtra extending upto 3.1 kms above mean sea level on 9th.

• The cyclonic storm, Phailin over east central Bay of Bengal moved slightly westwards, intensifi ed into a severe cyclonic storm and laid centred


at 0830 Hours IST , the 10th October 2013 near Lat. 14.5°N and Long. 91.0°E about 820 km southeast of Paradip, 870 km east-southeast of Kalingapatnam and 900 Km east-southeast of Vishakhapatnam. It intensifi ed into a very severe cyclonic storm and lay centred at 1430 Hours IST of today near Lat. 14.5°N and Long. 91.0°E about 820 km southeast of Paradip, 870 km east-southeast of Kalingapatnam and 900 Km east-southeast of Vishakhapatnam.

• An upper air cyclonic circulation lies over south Chhattisgarh and adjoining Telangana & Vidarbha extending upto 3.1 km above mean sea level.

• Another upper air cyclonic circulation lies over Saurashtra & neighbourhood extending upto mid-tropospheric levels.

• An east-west trough extends from Saurashtra & Kutch to centre of cyclonic storm across interior Maharashtra, south Chhattisgarh and north Andhra Pradesh upto mid- tropospheric levels.

Rain and fl oods associated with cyclone Phailin in Nepal:

The affect of cyclone was observed with thunderstorm activity in association with strong wind and heavy rainfall in the eastern region of Nepal in early morning on 13 October, the second day ( Maha Nawami ) of Dasai. However, the weather was fair and sunny in entire Nepal on 12 October, the fi rst day ( Maha Astami) of Dasai.

The storm advanced into north west affecting the central and western parts of Nepal on 13 October towards afternoon. Rainfall occurred for whole day on 14 and 15 October. The impact of the cyclone continued until 16 October afternoon affecting various parts of Nepal, however, far western region of Nepal left totally unaffected by the cyclone during the entire period of impacts of Cyclone in Nepal. Hence, almost all parts of the western region remained dry and enjoyed a fair weather during Dasai festival ( Fig 3).

The rainfall recorded at various places of Nepal are shown in Table 1.The rainfall amounts are small in fi gure but, the saturated land surface during the monsoon season explored fl oods in Kosi and Gandaki rivers in Nepal.

Fig 3. Cyclone Phailin advancing North West towards Nepal and adjoining areas on 12 October 2013 at 21:30 UTC.

Table 1. Rainfall in Nepal.

Stations

Rainfall (mm) on 13 ctober

2013

Rain (mm) on 14

October 20 13

Rain (mm) on 15

October 2013

Rain(mm) on

16 October 2013

Biratnagar 2.9 35.1 0 00Dhankuta 00 54.6 61.9 00Taplejung 00 40.0 52.5 6.2Kathmandu 00 43.9 21.5 0.2Pokhara 00 23.5 44.5 30.7Dang 00 3.0 12.8 NAJumla 00 Traces 00 TracesNepaljung 00 Traces 1.4 00Birendranagar 00 Traces 2.6 00

Source Department of Hydrology and Meteorology

Conclusion: The occurrence of cyclone in Indian Ocean and adjoining Bay of Bengal and Arabian sea is a common phenomenon during monsoon season in South Asia. However, late appearance of severe cyclonic storm such as Phailin towards the end of monsoon might be disastrous, as it may extend the monsoon period for several days which may solicit unexpected natural disasters in the country. It damages the agricultural products such as paddy and other outputs as well. Hence, the prolonged monsoon may be hazardous for human beings and it is essential to be noted with precautions.


An Introduction of Bamboo Porcupine Spur

Sah D.N., Ph.D. SDE, DWIDP

1. Introduction

Approximately 6000 rivers and rivulets with a total drainage area of about 194,471 km2 fl ow through Nepal; 76% of this drainate area is contained within Nepal. Based on available hydrological data, estimated annual runoff from river of Nepal is 220 billion cubic meter with average annual precipitation of 1530 mm, out of which 5.8 billion cubic meters is estimated as recharge and remaining 214.2 billion cubic meter as surface runoff. (Water Resources Strategy, Nepal, 2002).

There are three types of rivers in Nepal, classifi ed based on the nature of their source and discharge. The fi rst category is perennial rivers that originate in the Himalayas and carry snow-fed fl ows with signifi cant discharge, even in the dry season. These include the kosi, Gandaki, Karnali and Mahakali. The second category’s rivers originate in the Midlands or Mahabharat range of mountains and are fed by precipitation as well as ground water regeneration. They are Mechi, Kankai, Kamala, Bagmati, West Rapti and Babai rivers. Although these rivers are perennial, they are commonly characterized by a wide seasonal fl unctuation in discharge. The third category rivers originate from the Siwalik Range. These rivers are seasonal with little fl ow during the dry season, and characterized by fl ash fl oods during the monsoon.

Most of them originate from Mahabharat and Chure range and some from high up in the Himalayas and fl ow through the Hills into the lowland before they enter India and join the Gangas. These immense water resources hold out on one hand a promise of wealth and huge development potential for the nation and on the other hand, frequently loom over to people and environment as threat and menace. Every

year during the monsoon Nepal has to bear with major fl ood problem caused mainly by heavy rainfall and compounded by degraded environment. Flooded rivers carry heavy load of sediments causing erosion, damaging crops, destroying private and communal properties and infrastructures and threatening the survival of many villages. Therefore fl ood control measures rand very high in the priority list of many communities and especially of the poorer section of the population which suffer the most from the fl oods than better off families. Unfortunately conventional fl ood control measures such as embankment and spurs provide only a partial protection and they are technically very demanding and costly. Putting up such structures often exceed the resources especially the fi nancial capacity of the government. But fl ood control must be pursued in many fronts.

Tremendous volume of water that fl ows in hundreds of big and small rivers also frequently creates serious threats because of their potential for adverse effects. Minimizing these adverse effects require large amount of technical and fi nancial resources. Unfortunately, neither have rivers been properly harnessed to minimize their adverse effects nor have available water resources been fully utilized for benefi cial purposes.

Topographically, Nepal is a mountainous country. Mountains and hills account for about 80% of the total national land. The only exception is the Terai plain, a low and fl at land, stretching east to west in the southern part of the country along the Indian border. Nepal has unique topography with the altitude variation from 60- m at Jhapa in the south east to 8,848- m Mt. Everest in the north. Almost all of the rivers fl ow from northern mountains


and hills to southern Terai plain. Rivers originating from various form, high altitude topographic regions carry heavy sediment loads. On the one hand steep slope gradient, intense precipitation and sparse forest cover have made hills very vulnerable to erosion. On the other hand, these rivers cause heavy seasonal fl ood damaging agricultural land and properties in the hills and Terai. Weak and fragile geology of Nepalese hills compounded with intense rainfall during the monsoon season and decreasing vegetative cover often result in a debris torrent, laden with boulders causing threats to lives and property.

Most of the rivers collect very high gradient before entering into Terai, forcing them to transport heavy sediment load. As they enter onto the Gangetic plain, the rivers spread out and their gradients decrease abruptly. This results in a decrease in sediment transportation capacity. Such obstruction produces deposition of bed load causing the rivers to spread out inundating vast areas of cultivated land. Thus the fl ood problems in Nepal have geological, topographical, hydrological as well as manmade dimensions.

The main effort in the fl ood control measure in Terai should be to provide safer passage of fl ood water at minimum costs minimizing damage with an approach and technology suitable for prevailing Nepalese conditions. Nepal experiences major fl ood problems during the monsoon (July to October) caused by incessant heavy rainfall. The problems caused by heavy rainfall are bank erosion, inundation and fl ooding of land and properties and sedimentation. During the incessant monsoon rain a considerable areas of paddy fi elds, houses, roads and channels are fl ooded. Moreover, due to high sediment load, riverbeds rise up forcing rivers to change course, which in turn destroys vast areas of cultivated land.

Because of the aggressive lateral erosion, farmer search for a long time been desperate to devise means for fl ood control works. If the problem is discussed with local people, their demand will immediately be to construct spurs and embankment with boulder protection, that too, in gabion crates. Embanking of river is also not an ultimate solution to the fl ood problem. River training in the sense of channeling the whole of river length seems to be a solution to the recurrent fl ood problem. However river training for the entire stretch of the river is far too expensive and thus out of consideration. The costs will be high that not a single

river could be embanked within the resources available. Furthermore, aggradations of riverbed create constant threat to the embankment, even if they were constructed.

Because of the desperate need for the additional farmland in recent decades, farmers have the tendency to encroach upon fl ood plains and reclaim riverbeds, thus narrowing the natural river widths. This has made the problem of fl ood control even more diffi cult to tackle. They wish to embank the rivers within the natural riverbanks. Therefore, the planning engineers often face serious problems of land acquisition.

Almost all of the rivers fl owing in the Terai plain require some sort of fl ood controls measures.

Although Nepal Government spends millions of rupees every year for this purpose, it is far too little for the need. The available fi nancial resources from the government for one river may just be adequate for the protection of one village while several others remain endangered.

So it is beyond the capacity of government alone unless the affected people also contribute in one way of another to solve their own problem. They have to come out of this dependency syndrome and search for ways and means to protect themselves from recurrent fl ood. Instead of always looking for costly and hi-tech means, they should also embank on appropriate and locally affordable techniques with proven quality and success.

The rate of sediment deposition in Terai estimated by different researchers is as much as 5 cm to 30 cm in year. This is mainly the case on river originating from Chure range. Terai is fl at; the main river channels often are not able to contain the large volumes of discharge that occur during the monsoon. This commonly results in fl ooding of the surrounding agricultural area. Recurrent fl ooding and sediment deposition increasing river width are becoming serious problems of concerning in Terai.

Catastrophic events that cannot be controlled can, to some degree, be rendered less dangerous by advance planning and preparation. In addition to preparations for emergency response, rescue and relief, a number of actions will be taken to mitigate the effects of disasters in the water sector. Numerous studies have been conducted on low cost fl ood control system. However, no low cost, appropriate,


locally available, effi cient and emergent system has been developed.

2. Materials and Methods

Bamboo Porcupine is very effective method for fl ood fi ghting .It is highly used for cheap and best method in erosion control and to divert the unwanted fl ow of fl ood water these days. Even the diverted fl ow of Koshi River due to damaged embankment was controlled by fl ood controlling expert technician by RCC percupine and others.

Making 60mm to 80mm dia. Bamboo pile & hammering into the ground including cutting as per size, pointing the end, below ground with attachment of bamboo made cubical shape with 6 square faces is called block of percupine. Its confi guration of location and alignment depends on the direction of fl ow and discharge of water. Bamboo fabric made by nailling bamboo pieces & fi xing them in place by tying with 20 SWG wire or by nailling with 75mm. Nails at alternating points, fabric is kept on the side of u/s and d/s of percupine to control the fl ow of sedimented water to settle the sediment. Types of percupine may be difference as the discharge of fl ood water quantity.

Bamboo pile spurs can be constructed as impermeable spur as well as submerged spur. Permeable spur can be constructed from bamboo pile. Wooden piles can also be used where available as cheaper alternative. It is constructed transverse of fl ow to reduce velocity and induce sedimentation. It is found highly successful in rivers having high sediment load (Jha, H. et al., 2000).

A wide variety of materials is used in construction of spurs and groynes. According to the type of construction used, two broad classes of groynes may result – (a) Solid groynes which do not permit appreciable fl ow through them and (b) Permeable groynes or spurs which permit restricted fl ow through them. Solid groynes may be constructed of a core of sand or sand and gravel or soil as available in the river bed, protected on the sides and top by strong armour of stone pitching or concrete blocks. Other types are ‘balli” crates packed with stone inside a wire screen, or rubble masonry. The section of the groyne is to be designed in accordance with the materials used and the force of the fl ood. The head of a groyne needs special protection and generally provided with a launching apron in addition to increased pitching thickness. Permeable spurs generally consist of timber stakes or piles, driven into the river bed for some depth below the level of deepest anticipate scour, and joined together to form a frame work by other pieces of timber, the space in between being fi lled with brush wood or branches of trees. The toe of the spurs is often protected by a mattress of stone or other material. The permeable spurs, instead of defl ecting the current, slow it down, and induce silt deposition. They are thus especially useful in rivers which carry a considerable amount of silt in suspension. They are, however, of a more or less temporary nature and are particularly susceptible to damage by fl owing debris or ice. Again in boulder and gravel beds, pile driving is not feasible and permeable spurs have to be put up by weight down timber beams at the base by stones or concrete blocks; the other parts of the frame can then be tied to these beams at the base. (Singh, B., 1983)

3. Results

Technology appropriated with porcupine to site condition is affordable, sustainable and effi cient. This is provided with the observations made in the Ghurkauli River Training and Management Sub Project, Nepal.

Sixty percent of major natural disasters in the world occur in the Asia and Pacifi c region. Human activity mostly concentrated in fl ood plains along the river banks which are often convenient and attractive locations for settlement, transportation, agriculture, industries and economic activity. However, intensive urbanization in the fl ood plain areas may create fl ooding due to acceleration of runoff caused by rooftop, pavement and insuffi cient drainage. To solve this fl ooding problem usually structural fl ood control measures Porcupine


are constructed despite their high cost and diffi cult in land acquisition. Without proper control of urbanization, the existing fl ood control facilities become less effective. Moreover, upstream urbanization, irrigation project and deforestation cause more fl ooding, and damages in the downstream areas. Therefore it is important to introduce the non-structural fl ood control measures to support the structural fl ood control measures. (Tingsanchali, 1996). Preparation of piles involves pointing of tips of a number of logs to be used as piles required during the construction of fl ood fi ghting structures (The River Bureau, A Handbook of Flood Fighting Methods).

The reasons of failure of solid spur and embankments are classifi ed into followings four categories: improper alignment of embankment, scouring of the toe portion of revetment and spur dykes with insuffi cient apron in term of length and depth, improper connection of spur dykes with embankment, and sucking out of fi lling materials of spur dykes and embankment through the covering works i.e. gabions, concrete block etc. (Final Report, 1995).

References

1. Final Report, 1995. Effectiveness Study of River Training Works, Example of Success and Failure, Water Induced Disaster Prevention Technical Centre (DPTC), Pulchowk, Lalitpur, Nepal.

2. Jha, H. et al., 2000. Flood Controls Measures, Best Practices Report. First Edition, Kathmandu, Nepal.

3. The River Bureau, Ministry of Construction of Japan, A Handbook of Flood Fighting Methods, Published by All Japan Confederation of Flood Fighting (Defense), Administration (Management) Bodies.

4. Singh, B., 1983. Fundamentals of Irrigation Engineering. Published by Nem Chand and Bros: Roorkee 247667

5. Tingsanchali, T.,1996. Floods and Human Interaction. Experiences, Problems and Solutions. Professorial Inaugural Lecture. Water Engineering and Management Program, School of Civil Engineering, AIT, Bangkok, Thailand.

6. Water Resources Strategy, Nepal, 2002. Published by Water and Energy Commission Secretariat (WECS), Kathmandu, Nepal.

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1. BackgroundMahakali River also known as The Sharda, originates from the Greater Himalayas at Kalapaani at an altitude of 3600 m, joins with the Dhauli Ganga, Gori Ganga, Chameliya, Ram Ganga and the Sarju River on its route until it descends into the plains into India and known as Sharda, which meets the Ghaghra (Karnali in Nepal) in Indian Territory at about 100 km from the existing Upper Sharda Barrage at Banbasa.

The river borders the Nepalese Mahakali Zone and the Indian state of Uttarakhand. The river fl ows in a gorge section in the upper region. Mahakali fl ows for a length of 223 km length in Nepal and 323.5 km in India up to its confl uence with Ghaghra river.

River Basin Characteristics

Mahakali is one of the fi ve major river basins of Nepal which is shared with India and has a total basin area of 14871 km up to Upper Sharda Barrage, about 34 per cent of which lies in Nepal. The total catchment area is 17,818 km up to Lower Sharda Barrage.

In Nepal, It lies entirely in the Far Western Region of Nepal and in the Mahakali Zone which has four administrative districts - DarchulaBaitadi, Dadeldhura, and Kanchanpur District .

Important Towns and Villages in the River Basin

Besides many villages in both the banks of the Mahakali river, the important towns beside which it fl ows are DarchulaKhalanga, Jauljibi, Julaghat, Chandani, Dodhara, and Mahendranagar in Nepal. And Dharchula Bazar Balwakote, Jauljibi, Jhulaghat, Banbasa, Tanakpur, etc., in India lie to the west of Mahakali river. Photographs (Fig. 1 & 2) show two different developing stages of the part of DarchulaKhalanga before destruction.

Massive Flood in the River Basin

From the mid night of June 15, the fl ow in Mahakali started to rise, the people from the low land were shifted to safe places which usually happened to occure in the past as well. But this time it did not stop with it and continued to rise with huge debris with it and hit to many areas of importance, like residential,

commercial, recreational, religious and historical places and even in the areas of security importance. Hundreds of private and public buildings were collapsed and diminished in the massive fl ood. Major destruction as well as future threat is in the Khalanga Bazar the Head Quarter of Darchula district and its vicinity, like Dashrathnagar, Chhangru, Ghat Bazar, Tikar Kheda, Main administrative area (Police, Telecom, School etc), Hospital complex, Galphai bazar, Ghatta area, Namaskar etc. Besides these area there is huge loss of land and properties in different villages of Bramhadev, Dhap, Dattu, Uku and Lali VDCs, of Darchula District. The fl ood started to hit in the areas, in the morning and major distruction was done within 10/12 hrs, because of which the people could not protect their stationary properties, however the loss of life of only one human life has been registered from Dhap VDC.

June 17, 2013 Flood and the Master Plan of Mahakali Rehabilitation Works, Darchula

Mahendra Pd. Badu, SDEWIDP Div. No. 7 Dhangadhi

Fig. 1


It is natural for a river to damage to the weaker bank, the process is accelerated with the increase in discharge and the bed/suspended load. The left bank of the river on Nepal side was mostly unprotected or partially protected with some temporary structures while the right bank was protected with rigid structures and even reinforced with some concrete studs, especially in the Khalanga and its vicinity which naturally diverted the heavily loaded fl ood to the Nepal side and triggered the heavy bank cuts in the Khalanga area of Darchula. As a result the land occupied by some offi ce in Nepal on the left bank, before fl ood has now gone on right bank of the river. Similarly it was also happened on both the sides of the river in the D/S of it.

This fl ood now has left the message that our settlements in the river basin need to be protected suffi ciently considering the safety of the people and property on both the sides of the river. At the moment there are many buildings hanging over the bank on both the sides and are waiting for immediate start of reconstruction works. Government of Nepal is now planning to construct the retaining structures with inspection road, as that of Indian side, as far as possible. In this context, the issue has also been raised in the 4th JSTC (Joint Standing Technical Committee) meet to make a joint effort to understand the fl ood behaviour of Mahakali river and carry out mitigation measures. In the 4th JSTC It is agreed to form a mechanism at the local level to exchange information so as to minimize the effect of similar calamities in the future.

There is no discharge measuring devices in the area in the Mahakali river or in its tributaries, the discharge at Banbasa barrage (with the catchment area of 15544 sq km) shows the record fl ow of 5 lacks 44 thousand 476 cusecs on June 18, 2013. The catchment area of Mahakali with respect to the Bridge at Khalanga, Darchula is found to be 3421 sq km.

2. Master Plan of the Rehabilitation Works:

After the massive fl ood in the basin a technical committee led by the division chief of DWIDP-Dhanagadhi, reached the site on 20th June 2013 and started immediate response works to protect the fl ood affected areas. High level offi cials including the Chairman of the council of ministers and the the member ministers visited the site on the following days. On the recommendation of the council of ministers a high level technical team led by Regional Director MWRID, Surkhet, also visited the site inspected the emergency works and recommended the immediate rehabilitation works to protect the district H/Q Darchula from further damage. On 1st & 2nd, Oct. 2013 Director General of DWIDP visited the site and directed the division offi ce to accelerate the study works and the Master Plan of the rehabilitation works.

Rehabilitation And Protection Works

The whole area is categorized in two groups for the rehabilitation and the protection work namely the core area, that covers the Khalanga Bazar and its vicinity and the other area that refers to the area other than the Khalanga Bazar. The rehabilitation and the protection work is again divided in two groups as the emergency works and the infrastructure development works.

Emergency work

After the June 17, 2013 fl ood, immediate protection works were started especially for about 3 months during the monsoon. Some toe protection works with studs were constructed in the possible vulnerable sites especially in the core area of Khalanga. Since many buildings are still in a great risk of fl ood damage in a long stretch of the river, which cannot be protected at once in a shot, emergency work is hence expected to be continued during the project execution period. Table 1 shows the estimation of the emergency works.

Table 1: Budget and Expenditure for Emergency Work

Fiscal Year 2069/70 2070/712070/71

to 2075/76

Total

Budget allocated 5 million 14.5 million

19.5 million

Expenditure till (Dec. 2013) 5 million 8 million 13

millionFuture budget need @ 15 million per year

60 million

60 million

TOTAL (Rs) 92.5Source: DWIDP - Division No. 7

2.0.1 River Training InfrastructuresThe following infrastructures would be constructed to protect the river banks and to beautify the area left behind the recent fl ood. RCC Retaining Wall with studs, 4.3 km. Access road along the protection work.4.3 km. 4-6 m wide RCC block launching along the protection work. 8.5 km Gabion Toe Wall, 3 m height and 4.5 m launching. Slope stability and bioengineering works

Fig. 2


The whole protection work is divided in two phases and stages depending upon the site condition and the importance of the location. Similarly the protection measures applied also categorized from simple gabion toe wall protection to RCC retaining walls with counterforts and proper PCC block launching. District head quarter Khalanga is taken as the core area of protection where the RCC retaining walls are preferred, whereas the other area in the periphery of the core area within the Khalanga VDC and the area other than the Khaklanga VDC, like Bramhadev, Dhap, Dattu, Uku, Lalietc are also taken into account for the protection works. Table 2.2 shows the area and the length to be protected.

Table 2: Area and the Length to be Protected

S. No Area/VDC Location Protection

Length (m) Type of Protection Work Remarks

1 Khalanga Bazar (Core Area)

Dashrathnagar 550

R.C.C. Retaining wall with stud protection

Chhangru 450

GhatBazr 250

TinkarKheda 250

Main administrative area 950

Hospital Complex 250

Galphai Bazar 700

Ghatta Area 250

Namaskar 900

2 Other Villages of Khalanga VDC

Kimtadi, Khettebagar, Masinbaluwa 2000 Gabion Toe wall protection

Protection

3 Other VDCs Bramhadev, Dhap,Dattu,Uku and Lali 6500 Gabion Toe wall protection

4 Emergency Work Gabion Toe wall protection

Source: DWIDP-Division No. 7

3. Design Considerations

The design criteria for the fl ood protection structures for such a river in a boulder stage have been determined after reviewing different literatures regarding river training.The criteria have also been adopted on the basis of experiences of different disciplines working in similar fl ood control works.

Design Discharge and High fl ood level

Mahakali River is a border river and has no hydro-meteorological station for the measurement of the discharge in the basin, up to the border bridge at Khalanga (Catchment Area 3421 sq km). The fl ood estimation is either interpolated from the known discharge of Banbasa barrage (Catchment Area 15544 sq km) or to be calculated from the empirical formula. Different possible methods have been adopted to calculate the discharge in the basin to assume the high fl ood level. It is quite diffi cult to estimate the height of the High fl ood level (HFL) in such undefi ned section of the river, HFL estimation in this case is made from the fi eld observation with some 1.5 to 2 m free board allowances to overcome the huge velocity head likely to come in the fl ood time.

Depending on the high fl ood level estimation, the retaining walls

of varying heights are proposed for different stretches. Heights of 6, 8, 10, and 12 m are taken as the standard heights for the design purpose.

Design of Counterfort:

Minimum design height of the wall is required as 6 m, as mentioned above; the walls hence are reinforced with the counterforts to economise the cost of construction. On one hand it is quite diffi cult to estimate the foundation depth for the walls in such undefi ned channels on the other hand it is not easy to go up to the required foundation level, in the river in such a boulder stage with a slope of 1 in 100 to 1 in 80 in some stretches, it is advised to either anchor the walls on the rock or on big boulders underneath or to give some front cut-off or the shear key whatever is appropriate in the site. Foundation of the counterfort would be laid on the fi rm strata underneath, which naturally would need to be fl ushed with the lean concrete to give the even surface. Together with this 4-6 m of Block launching and 6-9 m of gabion launching is provided to protect scour at the toe of the wall. Furthermore the studs of 3m*2m are proposed at 10 m spacing to minimise the fl ood impact on the walls.

Backfi lling of the counterforts is to be done with the width depending on the site condition while the provision of the


minimum of 5.50 m roadway is made throughout the length as far as possible. Stairs are provided at appropriate locations to facilitate the people to go down the river banks for different purposes.

Together with the bio-engineering means, Breast wall of random rubble masonry (1:4) is proposed at appropriate locations for the hill slope protection. Suffi cient drainage facilities is provided with the provision of longitudinal and the cross drainage at appropriate locations.

4. Project Cost & Financial Plan

Cost of the Civil Work

Cost of the civil works of the protection work is illustrated in the Table 3

Table 3 : Component wise cost of the Civil Works

S. No Component Amount (Million) % of total

Core Area

1 Counterfort walls 893.03 43.77

2 Foundation/Toe Protection 569.38 27.91

3 Backfi lling, Roadway and Drainage Works 92.11 4.51

4 Hill slope Protection 193.18 9.47

Other Area

5 Other Villages of Khalanga VDC 50.00 2.45

6 Other VDCs 150.00 7.35

Both Area Emergency Work 92.50 4.53

Total cost of Civil works 2040.20


Project Cost Summary:

Mahakali is a border river, India has been protecting their settlement areas along the river while the Neplese people are living along the unprotected river banks. Because of the fact the recent fl ood adversely affected on the Neplese side on its major settlements. Being a border river, it has shifted the practical border in the basin in many places after the fl ood. River naturally attacks the unprotected bank and shifts towards it if one side of the bank is left unprotected. Shifting of the river in such a way will lead to the shifting of the practical border between the countries which ultimately requires not only huge money but comes to be almost impossible to acquire the land so went on the other side of the river. Because of the national interest linked with it sets the top priority for its execution.

The total fi nancial cost of Mahakali fl ood damage rehabilitation work is Nrs. 3,055,000,000 (Table 4) which includes the protection work of the core area with emergency protection work and the bank protection work along the river other than the district H/Q. The whole project work is divided in two phases, with 8 no of packages in Phase I and 5 in phase II with 5 years of total project period. Summary of the project cost and its yearwise fi nancial requirement of the project is shown in the table 4.

Table 4: Phasewise Financial Plan for Rehabilitation and Management Work

S.NFinance Required in Phase wise (Millions)

Phase/Fiscal Year Total Amount Allocation

1st Phase1 F.Y 2070/071 575.502 F.Y 2071/072 731.803 F.Y 2072/073 731.804 F.Y 2073/074 360.80

2nd phase4 F.Y 2073/074 310.005 F.Y 2074/075 345.10 Total Amount Nrs. 3055.00


5. Project Implementation Plan

The entire project has been planned to complete in fi ve years, from the Fiscal Year 2070/071 to the Fiscal Year 2074/75. The civil works as well as the Institutional Development works, techincal assistance, procurement of vechicles etc will be implemented simultaneously from the beginning.


GLOSSARY OF DISASTER TERMSAcceptable Risk

Degree of human or material loss that is perceived by the community or authorities as acceptable

All Hazards Approach

Dealing with all types of emergencies/disasters that may impact on communities and the environment using the same set of management arrangements and includes both natural and man-made hazards.

Capacity

“The combination of all the strengths, attributes and resources available within a community, society or organization that can be used to achieve agreed goals”

Chemical Hazards

Hazards involving chemicals or processes which may realize their potential through agents such as fi re, explosive, toxic or corrosive effects

Cluster

A “cluster” is essentially a “sectoral group” and there should be no differentiation between the two in terms of their objectives and activities; the aim of fi lling gaps and ensuring adequate preparedness and response should be the same. (IASC Guidance Note on Using the Cluster Approach Nov 2006)

Cluster Approach

The Cluster Approach aims to strengthen humanitarian response capacity and effectiveness in fi ve key ways: i) ensuring suffi cient global capacity is built up and maintained in key gap sectors/areas of response; ii) identifying predictable leadership in the gap sectors/areas of response; iii) facilitating partnerships and improved inter-agency complementarily by 18 Unoffi cial translation of Nepali version maximizing resources; iv) strengthening accountability; and v) improving strategic fi eld-level coordination and prioritization in specifi c sectors/areas of response by placing responsibility for leadership and coordination of these issues with the competent operational agency. (IASC Guidance Note on Using the Cluster Approach Nov 2006)

Cluster Leads:

A “cluster lead” is an agency/organization that formally commits to take on a leadership role

within the international humanitarian community in a particular sector/area of activity, to ensure

adequate response and high standards of predictability,

accountability & partnership. (IASC

Guidance Note on Using the Cluster Approach Nov 2006)

Command

The direction of members and resources of an organization in the performance of the organization’s

roles and responsibilities. Authority to command is established in legislation or by agreement and operates vertically within an organization.

Communications

Specifi cally, the means of communications, for example, roads, railways, telephone lines, radio,

television, fax, internet. Broadly, dissemination of disaster management messages using a variety of means to people and organizations at various stages of the disaster cycle.

Comprehensive Approach

The development of disaster arrangements to embrace the aspects of prevention preparedness, response and recovery.

Control

Control is the overall direction of the activities in a given operation.

Coordination

The bringing together of organizations and resources in accordance with the requirements imposed by the threat or impact of the emergency.

Coping

Coping is the manner in which people and organizations act, using existing resources within a range of expectations of a situation to achieve various ends. Coping capabilities are a combination of all the strengths and resources that are useful in reducing the effects of disasters.

Contingency Planning

A management process that analyses specifi c potential events or emerging situations that might threaten society or the environment and establishes arrangements in advance to enable timely, effective and appropriate responses to such events and situations.

Disaster

A serious disruption of the functioning of a community or a society causing widespread human, material, economic or environmental losses which exceed the ability of the affected community or society to cope using its own resources. A disaster is a function of the risk process. It results from the combination of hazards, conditions of


vulnerability and insuffi cient capacity or measures to reduce the potential negative consequences of risk.

Or

An event, either man-made or natural, sudden or progressive, the impact of which is such that the affected community must respond through exceptional measures.

Disaster Management

There could not be a single organization solely responsible for all aspects of disaster management.

The management task is to bring together, in an integrated organizational structure, the resources of many organizations that can take appropriate action in times of disasters.

Disaster Plans

An agreed set of arrangements for preventing, mitigating, preparing for, responding to and recovering from a disaster. A formal record of agreed disaster management roles, responsibilities, strategies, systems and arrangements.

Disaster Risk Management

A development approach to disaster management, this focuses on underlying conditions of the risks which lead to disaster occurrence. The objective is to increase capacities to effectively manage and reduce risks, thereby reducing the occurrence and magnitude of disasters.

Disaster Risk Management Arrangements

Linkages between the Offi ce of the Prime Minister through the various levels of government disaster committees, community response teams, national disaster management offi ce and emergency operations center (EOC)

Disaster Risk Reduction

The conceptual framework of elements considered with the possibilities to minimize vulnerabilities and disaster risks throughout a society, to avoid (prevention) or to limit (mitigation and preparedness) the adverse impacts of hazards, within the broad context of sustainable development.

Disaster Risk Reduction Plan

A document prepared by an authority, sector, organization or enterprise that sets out goals and specifi c objectives for reducing disaster risks together with related actions to accomplish these objectives.

Disaster Support Plans

Refers to those plans, which are designed to address specifi c hazards and are used in support of national disaster planning arrangements. Aircraft crashes are an

example of such plans.

ECC/Emergency Coordination Center

Facilities established to control and coordinate the response and support to an emergency.

Emergency Management Team

A group or team of disaster management personnel headed by an incident manager, which is responsible for the overall control of the emergency

ESLO/Emergency Services Liaison Offi cer

His/her task is the liaison and co-ordination of activities pre, post and during response.

Emergency Management

The organization and management of resources and responsibilities for dealing with all aspects of emergencies, particularly preparedness, response and rehabilitation called emergency management. It involves plans, structures and arrangements established to engage the normal endeavors of government, voluntary and private agencies in a comprehensive and coordinated way to respond to the whole spectrum of emergency needs. This is also known as disaster management.

Early Recovery

Decisions and actions taken after a disaster with a view to restoring or improving the pre-disaster living conditions of the stricken community, while encouraging and facilitating necessary adjustments to reduce disaster risk. Recovery (rehabilitation and reconstruction) affords an opportunity to develop and apply disaster risk reduction measures.

Hazard

A potential or existing condition that may cause harm to people or damage to property or the environment. The magnitude of the phenomenon, the probability of its occurrence and the extent and severity of its impact can vary. In many cases, these effects can be anticipated and estimated.

Or

A potentially damaging physical event, phenomenon or human activity that may cause the loss of life or injury, property damage, social and economic disruption or environmental degradation Hazards can include latent conditions that may represent future threats and can have different origins: natural (geological, hydro meteorological and biological) or induced by human processes (environmental degradation and technological hazards). Hazards can be single, sequential or combined in their origin and effects. Each hazard is characterized by its location, intensity, frequency and probability.

DWIDP Bulletin January 2014 Series XIV 25Hazard Analysis

That part of the overall planning process which identifi es and describes hazards and their effects on the community.

Or

“Identifi cation, studies and monitoring of any hazard to determine its potential, origin, characteristics and behavior”

Hazard Mapping

The process of establishing geographically where and to what extent particular hazards are likely to pose a threat to people, property and the environment.

Integrated or “All Agencies Approach”

Involves the inclusion of all relevant agencies and/or departments that can assist in the effective

implementation of disaster management arrangements.

Lead Agency

The agencies identifi ed as primarily responsible for responding to a particular disaster

Lifelines

Public facilities and systems that provide basic life support services such as water, energy, sanitation, communications and transportation.

Logistics

A range of operational activities concerned with supply, handling, transportation, and distribution of materials.

Mitigation

Measures, structural and non-structural, taken to reduce the impact of disasters.

Or

“Structural and non-structural measures undertaken to limit the adverse impact of natural hazards, environmental degradation and technological hazards”

People-centered Approach

While considering disasters as hazardous events, their occurrence is also viewed as the result of social, economic, and environmental conditions and practices. People, their livelihoods & welfare are the central concern.

Preparedness

Arrangements to ensure that, should a disaster occur, all those resources and services which are needed to cope with the effects can be effi ciently deployed.

or

The knowledge and capacities developed by governments, professional response and recovery organizations, communities and individuals to effectively anticipate, respond to, and recover from, the impacts of likely, imminent or current hazard events or conditions. Disaster Preparedness Activities and measures taken in advance to ensure effective response to the impact of hazards, including the issuance of timely and effective early warnings and the temporary evacuation of people and property from threatened locations.

Prevention

Regulatory or physical measures to ensure that disasters are prevented or their effects mitigated.

Or

“Activities to provide outright avoidance of the adverse impact of hazards and means to minimize related environmental, technological and biological disasters called Prevention”. Depending on social and technical feasibility and cost/benefi t considerations, investing in preventive measures is justifi ed in areas frequently affected by disasters. In the context of public awareness and education, related to disaster risk reduction changing attitudes and behaviour contribute to promoting a "culture of prevention".

Public Awareness

The process of informing the public as to the nature of the hazard and actions needed to save lives and property prior to and in the event of a disaster.

Recovery

The coordinated process of supporting disaster affected communities in reconstruction of the physical infrastructure and restoration of emotional, social, economic and physical well being.

Relief

The provision of immediate shelter, life support and human needs of persons affected by a disaster.

Resilience

The capacity of a system, community or society potentially exposed to hazards to adapt, by resisting or changing in order to reach and maintain an acceptable level of functioning and structure. This is determined by the degree to which the social system is capable of organizing itself to increase its capacity for learning from past disasters for better future protection and to improve risk reduction measures.

Resources

Any asset, physical, human, economic or environmental


which can be used to assist in achieving the objectives of the plan (people, equipment, relief supplies, water, roads, warehouses and money).

Response

Actions taken in anticipation of, during and immediately after a disaster to ensure that its effects are minimized and that people affected are given immediate relief and support.

Risk

The probability of harmful consequences, or expected losses (deaths, injuries, property, livelihoods, economic activity disrupted or environment damaged) resulting from interactions between natural or human-induced hazards and vulnerable conditions. Conventionally risk is expressed by the notation; Risk = Hazards x Vulnerability. Some disciplines also include the concept of exposure to refer particularly to the physical aspects of vulnerability. Beyond expressing a possibility of physical harm, it is crucial to recognize that risks are inherent or can be created or exist within social systems. It is important to consider the social contexts in which risks occur and that people therefore do not necessarily share the same perceptions of risk and their underlying causes.

Risk Assessment

A methodology to determine the nature and extent of risk by analyzing potential hazards and evaluating existing conditions of vulnerability that could pose a potential threat or harm to people, property, livelihoods and the environment on which they depend. The process of conducting a risk assessment is based on a review of both the technical features of hazards such as their location, intensity, frequency and probability; and also the analysis of the physical, social, economic and environmental dimensions of vulnerability and exposure, while taking particular account of the coping capabilities pertinent to the risk scenarios.

Risk Reduction

Selective applications of appropriate techniques and management principles to reduce either the likelihood of an occurrence or its consequences, or both.

Search and Rescue

The process of locating and recovering victims and the application of fi rst aid and basic medical assistance as may be required

Situation Report

A brief report which outlines the details of the emergency as they become known

Stakeholder

Any one who has a vested interest or impacts on disaster risk management, either negatively or

positively, and can include community members, local and central government, land owners, private enterprise, NGOs, Banks, development organizations, and the media.

Standard Operating Procedures

A set of directions detailing what actions could be taken, as well as how, when, by whom and why, for specifi c events or tasks.

Support Agency

Agencies that provide essential services, personnel, or material to support a control agency or affected persons.

Technological Disasters

Disasters arising from other than natural disaster causes and include biological, chemical, nuclear, transport and terrorist instigated disasters.

Technological Hazard

A hazard of a technological origin (man-made), as opposed to a hazard of natural origin

Vulnerability

A set of prevailing or consequential conditions composed of physical, socioeconomic and/or political factors that adversely affect the ability to respond to disasters. Vulnerabilities can be physical, social, or attitudinal and can be primary or secondary in nature. Strategies that lower vulnerability also reduce risk.

Or

The conditions determined by physical, social, economic and environmental factors or processes, which increase the susceptibility of a community to the impact of hazards.

Warning Systems

The purpose of warnings is to persuade and enable people and organizations to take actions to increase safety and reduce the impacts of a hazard, which can be either quick onset i.e., cyclones, fl oods or slow onset, famine or man-made such as fi res, explosion, chemical spills etc.

(Source: ISDR, IDRM Glossary of Disaster Risk Management Terminology)


Standards, Norms and Criteria: Hazard Categorization and Defi nitionGroup Category Type Sub-type

M e t e o r o l o g i c a l hazard

Storm Wind storm e.g. Tornado, strong windRain storm Extended rainfall

Torrential rainfallSnow stormHail/ice stormDust/sand stormThunder storm/lightning

Cyclone Tropical cycloneExtratropical cyclone

Extreme temperature Heat waveCold waveThermal shift?Freezing rain?

C l i m a t o l o g i c a l hazard

El Nino / La NinaStream shutdown Ocean stream shutdown e.g. North Atlantic

Gulf stream shutdownSea level rise Slow-onset SLR

Rapid-onset SLR e.g. Increasing melting of GLISExtreme SLR e.g. Collapse of WAIS

Glacier melting GLOMonsoon variation? Slow-onset M.V. * Global M.S., seasonality

Rapid-onset M.V.Drought Meteorological drought

Hydrological droughtAgricultural drought

Wildfi re Forest wildfi reLand wildfi re e.g. Bush, scrub, grass wildfi res

H y d r o l o g i c a l hazard

Flood Water-logging Due to extended rainfall and the low-lying topographyGeneral fl ood By location (e.g. riverine, coastal, urban, underground),

due to the capacity of drainageFlash fl ood [By triggering events (torrential rain, tsunami, storm surge, GLOFs)]

Regular fl ash fl oodMud fl owDebris fl ow

Tsunami seicheStorm surgeTidal wave

E n v i r o n m e n t a l hazard

Envi. degradation Desertifi cationDeforestation

Ecol. neglectPollution Air pollution e.g. Acid rain, radioactive cloud & soot

Surface water pollution e.g. Oil spill, effl uent contaminationGroundwater pollution

Waste disposal General waste disposalToxic waste disposal


Geological hazard Earthquake Tectonic earthquake Inter-plate earthquakeIntra-plate earthquake

Volcanic earthquakeVolcano eruption Lava fl ow

Gas & aerosolAshfall

Mass movement Snow avalanche Dry snow avalancheWet snow avalanche

Landslide LandslideRockslideRockfallDebris avalanche

Land subsidence SinkholeCollapseSubsidence

Soil liquefactionExpansive soilErosion Coastal erosion

Bank erosionDeposition Toxic chemical D.

Planetary hazard Outer-space fallout Meteorite/asteriodSpace debris

Biological hazard Epidemic disease Viral infect. D. e.g. Avian fl u, swine fl u, N1H1, SARS, chicken pox, small pox, AIDS(HIV), Measles

Bacterial infect. D.Parasitic infect. D.Fungal infect. D.Prion infect. D.

Endemic diseaseInsect infestation e.g. Grasshoper/locust swarms/killer bees/mosquitos

Animal attack Animal stampede e.g. elephantAnimal bite? e.g. dog

T e c h n o l o g i c a l hazard

Accident Transportation e.g. car, boat, train, airplane, spacecraft, etc.Explosion e.g. Boiling liquid, expanding vapour, hazardous

chemical Fire e.g Electric fi re, spontaneous combustion

Structure failure Dam failureBridge failureBuilding collapseOther structure failure

E q u i p m e n t malfunction

Equipment malfunction e.g. Design fl aw, illicit drugmaking & taking

A n t h r o p o g e n i c hazard

Social unrest Confl ict e.g. crowd violencePanicPlagueWarfare e.g. guerrilla & civil war Terror attack e.g. criminal extortion by virus & poisonsHostage takingHijackingFamine

Economic crisis Economic recessionMarket collapse

(Source: Global Risk Identifi cation Programme- GRIP )


Emergency Work Porcupine Spur, Lakhandehi River, Sarlahi

Sensi sa on Workshop Dang River Bank Erosion Control Structure

Field Study of Trainees of 21st ACT Annual Progress Review Workshop, 2069/70


21st Advance Course Training Participants & DWIDP Officials

Department of Water Induced Disaster Prevention (DWIDP)Pulchowk, LalitpurPost Box No. 13105, Kathmandu, NepalPhone: 977-1-5535407, 5535503, Fax: 977-1-5523528www.dwidp.gov.np

dwidp book format 2070 - dwidm.gov.np · senior divisional engineer editor ... technical centre...

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