inventory and integrated assessment of rivers and ... · and maintenance cost at serayu-bogowonto...

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Water Resources Engineering & Management

Inventory and Integrated Assessment of Rivers and Estuaries in Indonesia

Case Study: Serayu River, Central Java

Entin Agustini Karjadi1, Andri Iwan Pornomo2, and Devi Ulumit Tias3

1,2,3Ocean Engineering Program, Institut Teknologi Bandung, Jalan Ganesha 10,

Bandung

Email: [email protected], [email protected], [email protected]

Abstract. Proper Operation and Maintenance (O & M) activities are crucial to

ensure that infrastructure will continue to function effectively and efficiently.

Currently, due to lack of proper O & M, many facilities in Indonesia deteriorate

significantly soon after they have been built and become non-functional before

they reach their design life. In 2016, the Directorate General of Water Resources,

Ministry of Public Works and Housing of Indonesia has launched a campaign to

reactivate the O & M program to improve the sustainability of water resources in

Indonesia. This campaign is known as “Gerakan Cinta Operasi dan Pemeliharaan

Sumber Daya Air (CinOP SDA)”, which means the Movement for Love of Water

Resources Operation and Maintenance. One of the programs is on River

Maintenance and River Infrastructure O & M. A successful implementation of this

program requires a thorough and actual information of river system and its

infrastructures. This paper presents the necessary steps to conduct an inventory

and assessment of a river system, which is carried out at the Serayu River in

Central Java Province as an example. It is shown that the method is simple enough

to be implemented to any river in Indonesia. The final products of this study are

recommendations for the O & M activities and a database using GIS system of the

Serayu River as an example. A manual for river inventory and assessment is also

created, which can be readily applied to all Indonesian rivers and estuaries.

Keywords: river; estuary; infrastructure; inventory; integrated assessment;

sustainable; Serayu River; Operation and Maintenance; walkthrough; database.

1 Introduction

Although currently the exact number of rivers in Indonesia is not available [1], it is safe to say that Indonesia has thousands of rivers which benefit its people tremendously as a source of food and drinking, household, and irrigation water. Many rivers are also used for transportation, recreation, and as a source of hydroelectric power and construction materials such as sand and gravel. On the other hand, rivers can bring disasters such as floods that can cause loss of property and even lives. The risk of flooding increases by population growth and

Inventory and Integrated Assessment of Rivers and Estuaries in Indonesia,

Case Study: Serayu River, Central Java 247


unregulated use of rivers that can deteriorate their conditions and threaten their sustainability.

To maintain the sustainability of river system as well as to optimize the benefit and minimize the loss, the government has built some infrastructures on rivers such as dikes, weirs, and dams. Proper O & M activities are crucial to ensure that those infrastructures will continue to function effectively and efficiently. Meanwhile, the planning of O & M activities requires a thorough and actual information of river system and its infrastructures.

Until now, an integrated information on the condition of rivers in Indonesia has not been available. The existing data are not well-structured and difficult to access. Recognizing the importance of a detailed and actual river system information, the river and estuary data inventory throughout Indonesia needs to be completed immediately. What information needs to be inventoried, how to implement the procedures, i.e., what kind of necessary data assessment and analysis to be performed, and how the results are displayed, will be presented completely in the final product of this study by taking the Serayu River as an example.

Serayu River is located in Central Java Province (Figure 1). It spans from the northeast, with its source in the highlands of Mount Slamet in Dieng plateau, to the southwest and flows out to the Indian Ocean. The catchment area is about 4375 km2 and the main river is about 180 km long with 11 tributaries [2].

Figure 1 Map of the study location of Serayu River with its source in the

highlands of Mount Slamet on Dieng plateau and empty out to Indian Ocean.

248 Karjadi et al.


2 Purpose and Objectives

The purpose of this study is to implement inventory preparation procedures and subsequently to assess the condition of a river body and estuary system with the Serayu River taken as an example.

The objectives of this study are (1) to obtain technical data of the Serayu River system from its headwater to estuary, including its utilization, natural damages, and all of its infrastructures; (2) to identify and assess the condition of the Serayu River body system, its potential of disaster and development; (3) to provide recommendations for a sustainable management of the Serayu River in the present and future; and (4) to produce a manual of "Procedures for Inventory and Integrated Assessment of River and Estuary" that can be readily applied in Indonesia.

3 Method of Implementation

The method for inventory and integrated assessment of river and estuary implemented in this study is compiled based on (1) Technical Improvement Guidelines on Procedures of the Operation and Maintenance River and River Infrastructure [3], (2) Asset Management of River Infrastructure [4], (3) Circular Letter No. 05/SE/D/2016 on Guidelines for Operation and Maintenance of River Infrastructure and River Maintenance [5], and (4) Pilot Project of Inventory and Inspection of River Infrastructure for Analysis Study of Need Based Operation and Maintenance Cost at Serayu-Bogowonto River Basin [6]. The steps to carry out the inventory and assessment of river and estuary are as follows.

3.1 Secondary Data Collection

Secondary data collected are (1) map of the region; (2) data and information about existing river infrastructure; (3) data and information about monitoring post, heavy equipment, and other O & M support equipment.

3.2 River Walkthrough

River walkthrough is conducted by observing, taking notes, measuring, and documenting the physical condition and function of the river. If the depth and width of the river allow the boat to pass, then walkthrough is carried out through the waterway. Otherwise, walkthrough is carried out overland.

The expected result is to obtain a general description of the river, which includes: (1) Administrative regional boundaries from upstream to downstream; (2) Topographical conditions based on visual observation; (3) Land cover based on visual observation; (4) River utilization based on visual observations and




interviews; (5) River basins based on visual observations; (6) Interviews; (7) Activities carried out adjacent to the river based on interviews; (8) Stakeholders related to the river; (9) Problems that often occur and expectations of community based on interviews; (10) Documentation in the form of photographs and videos by drone.

3.3 Inventory and Identification of River Infrastructure

Inventory and identification of river infrastructure are implemented by observing the physical condition of all infrastructure on the river together with the condition of their function.

Data of physical condition of each infrastructure include its dimension, condition of constituent material, condition of infrastructure body, and condition of infrastructure foundation. The condition of the infrastructure’s function is presented in the form of a description of how well the infrastructure functions and the situation on the river adjacent to it. The inventory results are accompanied with photographs complete with notes and comments. Any damages found are also documented with photos. The description of the damages and the guideline for their locations are shown using sketches.

3.4 Performance Assessment of River and River Infrastructure

Infrastructure included in the performance assessment are [4]: (1) river dikes; (2) revetment: (3) jetty; (4) crib; (5) spillway; (6) flood gate; (7) flood pump; (8) rubber dam; (9) retention pond; (10) groundsill, sabo and check dam; (11) inspection road; (12) H3 monitoring station; (13) O&M office, laboratory, warehouse buildings, and guard house; (14) O&M heavy equipment and support vehicles; and (15) information and communication equipment. It is important to note that any infrastructure encountered during walkthrough (other than mentioned above) must also be inventoried.

Based on the actual field conditions, the river and its infrastructure are graded using certain criteria given in [6]. Table 1 to Table 6 show the criteria pertinent to the Serayu River. Subsequently, the performances of the river and each of its infrastructure are assessed using values given in Table 7 [4, 5] to determine their final performance grades.

250 Karjadi et al.


Table 1 Assessment Criteria of Physical Condition for Natural River

No Point Physical Assessment Criteria

1 10 • River banks have been totally disturbed by humans so that no vegetation

remains and human activities have dominated the waterline.

• River environment is not maintained (it is not clean, it is not neat,

buildings are placed haphazardly on the river).

2 25 • Most of the river banks are disturbed by human activities so that only a

few vegetation remains and human activities have dominated the

waterline.

• Humans who use the river only maintain their own environment without

regard to river conditions.

3 40 • A small part of the river bank is disturbed by human activity, but most

of the river banks are still in good natural condition with indications of

thriving native vegetation.

• There is no non-organic trash in the river environment.

4 50 • River banks are still not disturbed with indication of thriving indigenous

vegetation.

• There is no non-organic trash in the river environment.

Table 2 Assessment Criteria of Function for Natural River

No Point Function Assessment Criteria

1 10 • The river surface is filled with water vegetation and/or trash, so the

function of the river to drain the water becomes disturbed.

• There is a landslide or plant on the river bank, so the ability of river to

accommodate water is not optimal.

2 25 • The river surface is filled with water vegetation and/or trash, so the

function of the river to drain the water becomes disturbed.

• There is a small landslide or vegetation on the river bank, so the ability

of river to accommodate water is not optimal.

3 40 • There are few water vegetation and/or trash, so the function of the river

to drain the water becomes disturbed.

• There are no landslides or vegetation on the river bank, so the river's

ability to accommodate water is optimal.

4 50 • River surface clean from water vegetation and trash.

• There are no landslides or vegetation on the river bank, so the river's

ability to accommodate water is optimal.




Table 3 Assessment Criteria of Physical Condition for Movable Weir


1 10 • There is a landslide on the movable weir.

• The bridge floor is broken and collapsed.

2 25 • There are cracks at the crest and there are loose stones.

• There are cracks, fractures, hollow part, and scouring at the tip of stilling

basin.

• The basic structure of the weir is eroded, hollow, and hanging.

• The condition of the wing wall is cracked, broken, and there are loose

stones.

• The weir’s gate is blocked, broken, cannot be closed/opened properly, the

door handle is bent and the mechanism is damaged.

• There is trash and landslides in the upstream river channel.

• peilschaal is broken and unreadable.

3 40 • Crest conditions are not cracked or broken, and there are loose stones.

• There is no hollow part and scouring on the stilling basin.

• There are wild vegetation on the base of the structure and walls.

• There is trash in the upstream river channel.

4 50 • The condition of the movable weir, consisting of the spillway crest,

stilling basin, base of the structure, wing walls, gates, upstream river

channel, and the peilschaal are not damaged and cracked, so the movable

weir can operate optimally.

• There is no trash and there is no landslides in the upstream river channel.

Table 4 Assessment Criteria of Function for Movable Weir


1 10 • There are landslides and collapsed structure, so its function to

accommodate the flow of water and maintain the water surface elevation

is not optimal.

2 50 • Infrastructure is in good condition, so its function to accommodate the

flow of water and maintain the water surface height is optimal.

252 Karjadi et al.


Table 5 Assessment Criteria of Physical Condition for Retention Pond


1 10 • Erosion in the catchment area of the retention pond has increased.

• Structure of existing retention pond collapsed, damaged, and destroyed.

2 25 • The inlet/outlet gate is blocked, broken, cannot be closed/open properly,

the handlebars are bent, and the mechanism is damaged.

• Crest of embankment around retention pond collapsed and leaked; slopes

landslides and wild vegetation growth exist.

• Embankment slopes have landslides, holes, and wild vegetation growth

exists.

• Retention pond full of sediment and of weeds.

• Peilschaal is broken and unreadable.

3 40 • The inlet / outlet gate is not blocked, the gate is in good condition, can be

closed/open properly, the handlebar is not bent, and the mechanism is in

good condition.

• Crest of embankment around retention pond are not collapsed and

leaking, no slopes landslide, no wild vegetation growth.

• Embankment slopes have no landslides and holes, but wild vegetation

growth exist.

• Peilschaal is readable and undamaged.

4 50 • The inlet/outlet gate is not blocked, in good condition, and can be

closed/open properly, the handlebar is not bent, and the mechanism is in

good condition.

• No part of the crest of embankment around retention pond collapses or

leaks, no slope landslides, and no wild vegetation growth.

• No landslides, no holes, and no wild vegetation growth on embankment

slopes.

• Retention pond is clean from sedimentation.

• Peilschaal is readable and undamaged.

Table 6 Assessment Criteria of Function for Retention Pond


1 10 • High sedimentation in retention pond; its construction has been

disintegrated, so its function to store water is not optimal.

2 50 • The retention pond is in good condition, so its function to store water is

optimal.




Table 7 Matrix of Physical Condition vs. Function for River and River

Infrastructure

Assessment

Physical Condition

50

Excellent

40

Good

25

Adequate

10

Poor

Fu

ncti

on

10

Poor 60 50 35 20

25

Adequate 75 65 50 35

40

Good 90 80 65 50

50

Excellent 100 90 75 60

> 70 Low Risk = Good Performance = Preventive Maintenance

50 – 70 Medium Risk = Adequate Performance = Corrective Maintenance

< 50 High Risk = Poor Performance = Rehabilitative

3.5 Follow-up Recommendations

The final objective of the performance assessment is the subsequent O & M follow-up plan, i.e., whether the river and its pertinent river infrastructure require a preventive (> 70), corrective (50-70), or rehabilitative (< 50) maintenance [3 - 5].

Preventive maintenance is applied to river infrastructure that has a low risk of failure (> 70) or a good performance. This maintenance is a preventive measure with the following criteria.

- Activities to maintain the infrastructure existence and in accordance with the level of performance of planned services.

- Activities to be carried out continuously or scheduled periodically and do not require a design calculation.

Corrective maintenance is applied to river infrastructure that has a moderate risk of failure (50-70) or an adequate performance. This maintenance is a corrective action with the following criteria.

254 Karjadi et al.


- Activities to correct or refine ineffectiveness of performance. - To make emergency repairs to deal with sudden infrastructure

damage.

Rehabilitative maintenance is applied to river infrastructure that has a high risk of failure (< 50) or a poor performance. This maintenance is a recovery act which include repairing and rebuilding activities.

4 Performance Assessment of Serayu River

In this study, a performance assessment is conducted on the Serayu River as an example. The main Serayu River is 176 km long and categorized as a natural river [4]. In this study it is divided into 3 (three) sections, i.e., upstream (48 km), middle (95 km), and downstream (33 km) sections.

The assessment results for the upstream, middle, and downstream sections of the river are shown in Figures 2, 3, and 4, respectively. The condition of the upstream section of the river (length of 48 km) is still very good (90) with no apparent effects from human activities. There are few locations of trash piles and sand mining in the middle section of the river (length of 95 km), but its overall condition is also good (80). The condition of the river decreases in the downstream section of the river (length of 33 km) with performance index of adequate (65). There are four locations of significant trash piles, and thirty locations of sand mining. Although sand mining activities have the benefit of maintaining river depth on those locations, but they also cause the river water to become murky. In addition, the loading and unloading activities have caused the destruction of the river bank. A regulation to control sand mining activities is needed to prevent more damages to the river.

There are six bridges, one movable weir, and one retention pond on the Serayu River. Bridges are not considered as river infrastructure, therefore they are inventoried only and are not assessed. The results of retention pond and movable weir performance assessment are shown in Table 8 and Table 9, respectively. Both the performance of retention pond and movable weir are good (90) and require only preventive maintenance.




1 :

a. Classification : Natural River

b. Ordo : 1

c. River Basin : Serayu Bogowonto

d. District : Cilacap, Banyumas, Purbalingga,

: Banjarnegara, and Wonosobo.

e. Section : Upstream

f. Length : 48 km

3

- Trash on the river bank :

- Sand Mining :

- Erosion of River Banks :

4

- Physical Condition : 40

- Function : 50

- Total Performance Index : 90

- Performance Category : Good Performance - Low Risk

- Assessment Background :

- Action Recommendation :

0 location

0 location

Assessment of River Performance

Physical river : The river is in a good condition. There

are no erosion and piles of trash.

River function : The function of river to flow and hold

water is very good.

(1) Maintain the river naturality. (2) Install a warning

sign to prohibit dispose of trash in the river. (3) Ensuring

business legality of sand mining.

0 location

River Name Serayu

2 Location

River Condition

Figure 2 Assessment result for upstream section of the Serayu River.

256 Karjadi et al.


1 :


b. Ordo : 1

c. River Basin : Serayu Bogowonto



e. Section : Middle River

f. Length : 95 km

3


- Sand Mining :


4


- Function : 40


- Performance Category : Good Performance - Low Risk


- Action Recommendation : (1) Maintain the river naturality. (2) Install a warning

sign to prohibit dispose of trash in the river. (3) Ensuring

business legality of sand mining.

1 location

2 locations

11 locations


Physical river : The river is in a good condition. There

are no erosion and piles of trash.


water is good.

River Name Serayu

2 Location

River Condition

Figure 3 Assessment result for middle section of the Serayu River.




1 :


b. Ordo : 1

c. River Area : Serayu Bogowonto



e. Section : Downstream River/Estuary

f. Length : 33 km

3


- Sand Mining :


4


- Function : 40


- Performance Category : Adequate Performance - Medium Risk


- Action Recommendation : (1) Install a warning sign to prohibit dispose of trash in

the river. (2) Ensuring business legality of sand mining.

(3) Write letters to the local government regarding

business legality issues and loading and unloading

activities that cause the destruction of the river bank. (4)

Regular clean up of trash on the river bank. (5) Organize

community involvement on river O&M activities.

4 locations

30 locations

4 locations


Physical river : There are sand mining activities that

cause the river to be murky.


water is good. Sand mining activities actually have

benefits for maintaining river depth, which means

maintaining its function to flow and hold water.

River Name Serayu

2 Location

River Condition

Figure 4 Assessment result for downstream section of the Serayu River.

258 Karjadi et al.


Table 8 Results of Movable Weir Performance

Assessment Component Point (10 – 50) Reasons

1. Top 40 Top is not cracked, broken, and there are loose stones.

2. Body 40 There is no hollow part and scouring on the stilling basin.

3. Foundation 40 There are wild vegetation on the base and walls.

4. Material 40 The material condition is overgrown with wild vegetation.

Value of physical condition

(Average component No.1 – No.4)

40 Good

Function Condition Value

Point (10 – 50) Reasons

50 Infrastructure is still in good condition, so its function to

accommodate the flow of water and maintain the water surface

elevation is optimal.

Infrastructure Movable Weir

Total Point 90

Risk of Failure Low Risk

Performance of O & M Good Performance

Action P lan for O & M Preventive Maintenance




Table 9 Results of Retention Pond Performance

All of the inventory data and assessment results are displayed using a GIS system, which include documentations, maps, and performance assessment results. This GIS system for the three river sections of the Serayu River will be updated regularly as a record keeping of the data. The display of the GIS system for the Serayu River is shown in Figure 5.

Assessment Component Point (10 – 50) Reasons

1. Top 40 Top of dam around the retention pond is in a good condition,

slopes do not slide, no grass but wild bushes growth exists.

2. Body 40 The embankment slope does not slide, no holes, no grass but

wild bushes growth exists.

3. Foundation 40 There are wild vegetation growths exist on the base and

structure walls.

4. Material 40 Material of the retention pond is covered by overgrown wild

vegetation and the structure is not damaged or collapsed.

Value of physical condition

(Average component No.1 – No.4)

40 Good

Function Condition

Point (10 – 50) Reasons

50 Retention pond is covered with wild vegetation, but the

reservoir is in good condition, so its function to store water is optimal.

Infrastructure Retention Pond

Total Point 90

Risk of Failure Low Risk

Performance of O & M Good Performance

Action P lan for O & M Preventive Maintenance

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Figure 5 Display of GIS system for the Serayu River.

5 Summary and Conclusions

In this study, the inventory and integrated performance assessment method of river and its infrastructure has been compiled and applied to the Serayu River as an example. It is shown that the method can be readily implemented to any river in Indonesia.

For inventory and performance assessment, the Serayu River is divided into upstream (48 km), middle (95 km), and downstream (33 km) sections with the assessment results of good performance, good performance, and adequate performance, respectively. A corrective maintenance is required for the downstream section while for the upstream and middle sections of the river only a preventive maintenance is required.

Infrastructure of the Serayu River are six bridges, one movable weir, and one retention pond. Bridges are not considered river infrastructure, so bridges are inventoried, but not assessed. The performance assessment results of retention pond and movable weir are both good and only a preventive maintenance is required.




To maintain the preservation of Serayu River system, the inventory and performance assessment activities should be conducted annually, which requires 5 observers and 36 workers for the 176 km total length of the Serayu River. In addition, community involvement on the implementation of the O & M of the river and its infrastructure is also very important.

References

[1] http://lipi.go.id/berita/indonesia-belum-miliki-data-jumlah-danau-dan-

sungai-yang-akurat/17078 [Accessed on 07/18/2017].

[2] http://hywr.kuciv.kyotou.ac.jp/ihp/riverCatalogue/Vol_03/03_Indonesia-

8.pdf [Accessed on 07/18/2017].

[3] Directorate General of Water Resources, Technical Improvement

Guidelines on Procedures of the Operation and Maintenance River and

River Infrastructure, Ministry of Public Works and Housing of Indonesia,

2016.

[4] Directorate General of Water Resources, Asset Management of River

Infrastructure. Ministry of Public Works and Housing of Indonesia, 2016.

[5] Directorate General of Water Resources, Circular Letter No.

05/SE/D/2016 on Guidelines for Operation and Maintenance of River

Infrastructure and River Maintenance. Ministry of Public Works and

Housing of Indonesia, 2016.

[6] Directorate General of Water Resources, Pilot Project of Inventory and

Inspection of River Infrastructure for Analysis Study of Need Based

http://lipi.go.id/berita/indonesia-belum-miliki-data-jumlah-danau-dan-sungai-yang-akurat/17078

http://lipi.go.id/berita/indonesia-belum-miliki-data-jumlah-danau-dan-sungai-yang-akurat/17078

262 Karjadi et al.


Operation and Maintenance Cost at Serayu-Bogowonto River Basin.

Ministry of Public Works and Housing of Indonesia, 2016.

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