sustainability of groundwater use for irrigation in northwest bangladesh
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Sustainability of Groundwater Use for Irrigation in Northwest Bangladesh. Sustainability ?. Sustainability. R. t. R-Resource use GW use indicates depth of GWT in negative value. Sustainability Indicators. Environmental. Sustain -ability. Social. Economic. Social indicators - PowerPoint PPT PresentationTRANSCRIPT
Sustainability of Groundwater Use for Irrigation in Northwest Bangladesh
Research Team
Nepal C. DeyMd. Abdur RashidRatnajit Saha
Research AdvisorMahabub Hossain
Sujit K. BalaAKM Saiful IslamAhsan A. Shopan
Sustainability ?
Sustainability
•R-Resource use•GW use indicates depth of GWT in negative value
t
R
SocialEconomic
Environmental
Sustain-ability
Environmental Indicators Groundwater table River water contri. to GW Precipitation Groundwater withdrawals Well intensity Evapo-transpiration (ET) Major crops and areas Wetland area Change in crop type Conservation
Social indicators No. of people practicing groundwater recharge methods No. of people using alternative sources of water for irrigation or other purposes Peoples’ perception in management
Economic indicators Financial Profitability Economic profitability
Sustainability Indicators
Challenges Sustainability of GW use for irrigation is becoming a
vital concern in many countries of the world, Bangladesh in particular, mainly NW of Bangladesh-where GW declines 5-10m in the dry period
(Extracting GW > Recharge capacity)
Contribution of GW for irrigation has increased by 2.5 times after 20 years
Recurrent below-average rainfall, higher temp causing drought, increased ET, delayed monsoon, dry-up of surface water bodies including ponds, rivers and thus lowering of GWT in the aquifer leading water crisis are some important.
Withdrawal of GW
Challenges (contd.)
Defects in present IWM practices has been identified. If water is managed properly, BGD can save addl. amount ≈ 1/6 of the total BGD
Budget for FY 2003-4 (USD 8,962 million) (Deyet al., 2006), and also similar to the ADP budgetof Bangladesh for FY 2009-10 (USD 4072million).
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Irrigation cost increased many folds causing threatens the economic viability of future crop production.
Irrigation cost in Bangladesh = > 4times higher than India, 6 times than Thailand and Vietnam. This is mainly because of dependence on GW irrigation
Objectives of the study
quantitatively assess the trends in water table depths and crop areas in the designated study area for the past 30 years.
financial and economic profitability of different crops along with likely changes over time due to declining water tables.
recommend policies for sustainable use of irrigation water in northwestern Bangladesh.
In addition, we worked on the following objective-
estimate cost of excess water lifted for irrigation.
Methodology
Study AreaRajshahi, Pabna, Bogra, Rangpur, Dinajpur District of Northwest Bangladesh
Geographically, the study area extends
230 48’ 14.3’’ to 260 03’ 16.8’’ latitudes and
880 18’ 44.99’’ to 890 43’ 50.71’’ longitudes.
Data CollectionPrimary Data and Information
Sample survey through structured questionnaire (Total number of farm household were 450 where 150 marginal, 150 small and 150 medium/large household) Focus Group Discussion (Five sub-district from five districts of NW Bangladesh) Consultation Meeting Workshop
Data for ET estimationLocation: Five Upazilas from five districts in NW region.
RS Data: MODIS satellite images & Landsat 7 ETM+ were used in this study.
Field coordinates of 131 Boro rice fields located in the selected 5-upazilas were collected using hand held GPS.
Secondary Data Data Type Duration Source
Groundwater table depth 1981- 2011 BWDB, BMDA and BADC
Surface water level (25 stations data) 1981- 2010 BWDB
Surface water discharge 198 1-2011 BWDB
Major crops and area 1981- 2011 BBS
Meteorological data(Rainfall, Tmax, Tmin, Humidity, etc.)
1981- 2011 BMD
Data analysisSoftware SPSS 16.0 and MS Excel ILWIS 3.4 and Arc GIS 9.2 software for image processing and analysis Arc GIS 10 - used for mapping.
Financial profitability analysis of major crops : Formula used ∏ = P1Q1 + P2Q2 - ∑PiXi – TFC
Economic profitability/comparative advantage of major crops: Border price measured at Farm gate (Import Parity) : Pj = Pj
b + Cjm – Cjd
Border price measured at Farm gate (Export Parity): Pi = Pib E0-Ci
Nominal protection (NPC) expressed as: NPCi = Pid/Pi
b
Effective protectionEPC =
Value of output at domestic price - Value of traded inputs per unit of output at domestic price
Value of output at world price converted at the official exchange rate
- Value of traded inputs per unit of output of world prices converted at the official exchange rate
Comparative advantage of crop production
Domestic resource cost (DRC)
Forecasting of irrigation cost
Autoregressive Integrated Moving Average or ARIMA (p,d,q) models used.
An AR(p) model has the form: Yt = a1Yt-1 + … + apYt-p + et
Estimation of ETSEBAL and FAO Penman-Moneith :
E H Go Rn
Where, Go – Soil heat flux, W.m-2
H – Sensible heat flux, W.m-2
λE – Latent heat flux, W.m-2 associated with ET
FAO Penman-Monteith method
Figure : Components of the Energy Balance
Normalized Differentiate Vegetation Index (NDVI) Map
Vegetation indices over NW regionGoB-BRAC weather station for climatic data
ET++
Excess Water
Precipitation
42 98.0162.032.0100
15.237NDVIrr
r
T
R
Goo
o
o
n
Estimation of Excess Water
)(WirrrementwaterrequiIrrigation
dWaterTotalLifterExcessWate
Result and DiscussionGroundwater table depths
Declining trend of GWT overtime
Fig . Changes in depth of GWT depth (Jan-May) over time.
Fig . Map of depleted upazilas in five districtsName of depleted upazilas:
River water level
Fig. Northwest region river water level fluctuation (yearly avg.)
Fig. Changes in river water level (a- maximum, and b-minimum)
River water discharge
RWL (Yearly avr.)
20.1m
18.3 m
RWD (Yearly avr.)
90.8
56.9m3/sec
Fig. Relationship between RWL & GWT
Figure (a-e). Change in crop area over time at (a) Rangpur; (b) Dinajpur; (c) Rajshahi; (d) Pabna and (e) Bogra district
Changes in crop areas 10 major crops’ area has increased 31915 (hectare) where boro alone increased more than 9 times during 1980/81 to 2009/10.
Area (Hectare)
Δ (09/10-00/01 )
Δ (09/10-80/81)
Bogra 7061 27753
Dinajpur 7035 33142
Pabna 3355 21158
Rajshahi 10193 44076
Rangpur 2200 31915
Financial profitability of Five major rabi season crops
Figure: Cost and return of different crops cultivation
Figure: Farm Category wise Benefit Cost Ratio of Boro Rice Figure: Region wise Benefit Cost Ratio of Boro Rice
District Costs of boro (Tk/ha)
Yield (T/ha)
Rajshahi 96,839 5.819
Pabna 96,080 6.483
Bogra 90,378 6.395
Rangpur 87,883 6.125
Dinajpur 86,583 6.192
Districts Major Cropping Patterns Suggested Crops according to cropping pattern and BCR
Dinajpur 1. Boro-Fallow-T. Amon2. Wheat-Jute/Maize/Mugbean-T.Amon
Wheat production should be emphasized
Rangpur 1. Potato-Boro-T. Amon2. Potato-Maize-T. Amon
Potato/ Maize production should be emphasized
Bogra 1. Potato-Boro-T. Amon2. Mustard-Boro-T. Amon
Potato/Mustard production should be emphasized
Rajshahi1. Wheat-Fallow-T. Amon2. Mustard-Boro-T. Amon3. Chickpea-Fallow-T. Amon
Wheat/ Chickpea production should be emphasized
Pabna 1. Wheat-Jute-T. Amon2. Boro-Fallow-Lentil
Wheat/ Lentil production should be emphasized
Major Cropping Patterns and suggested crops in the study area
Crops BCRRajshahi Pabna Bogra Rangpur Dinajpur
Boro 1.12 1.13 1.25 1.22 1.18Wheat 1.34 1.36 - 1.31 1.37Potato - - 1.35 1.31 1.24Mustard 1.30 1.28 1.35 1.28 1.36Lentil - 1.49 - - -
Actual and projected
irrigation cost (Tk/ha)
0
5000
10000
15000
20000
Year
Tk
/ha
Actual Irrig. Cost Forecasted Irrig. Cost
Simulation of time path of boro rice production cost and GWT depth
1
Using forecasted irrigation cost (other things reaming same) the financial and economic analysis of boro rice
Year Forecasted irrigation cost
(Tk/ha)
Total cost
(Tk/ha)
Gross return(Tk/ha)
Net return(Tk/ha)
BCR DRC
2012 11136.74 91928 107234 15306 1.17 0.7142015 12085.35 92876 107234 14358 1.15 0.7202020 13562.45 94353 107234 12881 1.14 0.7302025 15041.48 95832 107234 11402 1.12 0.7392030 16520.50 97312 107234 9923 1.10 0.7482031 16816.31 97607 107234 9627 1.10 0.750
Change in Wetland area in selected Districts
Changes of NDVI and ET in 2010
21 January 11 April21 January 11 April
ET estimated by SEBAL and Penman-Monteith methods.
Intensity of TW
TW intensity: 6.9 to 36 nos/ km2
DTW became almost double
STW reached more than five time higher
TW increased 8.5 times where irrigated land increased 1.6 times.
Fig.(a) Intensity of TWFig. b) Increase of TW over time
Fig.(c) Increase of irrigated area over time
Excess water extracted
Fig. Water requirement & Excess water lifted
Fig. NW region Irrigation water requirement and extraction
Amount extracted was highest in Badarganj of Rangpur district followed by Godagari of Rajshahi, Birampur of Dinajpur, Chatmohor of Pabna district, and least in Dhupchancia of Bogra district
Environmental Impact12464.8
T (2010)
Pesticides use3895 T (‘73-90)
Polluted water percolation Saline water intrusion
OC N SP K ZnNutrient mining
Socio-economic impact
Jobless Time and Energy loss for collecting water
Health problemsEconomic loss from pisciculture - drought
Nutrition deficiency
Conclusion
Sustainability of groundwater use for irrigation in northwest Bangladesh has been identified as a matter of concern.
The key impediments of sustainability of groundwater use for irrigation are identified as over exploitation of GW with declining trend, increase of TW nos. and pumping of excess water, increase of boro area, decline of river water flow, decrease of wetland area, less rainfall in the dry period, increase of irrigation cost, poor water management and so on.
Policy recommendations
1. To harmonize boro rice cultivation with other high valued winter crops.
2. Managed Aquifer Recharge (MAR) should be undertaken as a national programme and strategy considering different regional contexts by adopting a series of activities like harvesting of surface and rain water and their storage and conservation through excavation of existing canals, ponds, khals, and water bodies in massive scale.
3. To establish independent Water Regulatory Authority (WRA)/Groundwater Directorate (DR) or any other existing bodies like BADC, DAE might be used for establishing governance and management of groundwater resource to fix and regulate the water tariff system and charges as per Policy Framework.
4. Water User Association (WUA) rooted strong small holder irrigation community should given statutory powers to fix rate determined by WRAs/badc/dae.
5. Optimization of command area of each DTW and STW though consultation with Water User Association where electric connection to pumps is the key component for regulation on GW use and to be realized phase wise i.e., with short term, medium term and long term planning. 6. Irrigation water price should be determined as a rule on volumetric basis in order to meet equity, efficiency and economic principles.
Policy recommendations (contd.)
7. Modern water Management technology liker alternate wetting and drying (AWD), water saving technology like hose pipe irrigation, drip irrigation, drought tolerant crop variety, etc. would bear no value without carrying out irrigation volumetrically.
8. Plan of Action (PoA) in line with basic policies like NAP, PRSP, CIP, NAPA, etc might be formulated under proposed GD or WRA or exsisting BADC or DAE on short term (ST), medium term (MT) and long term (LT) basis.
9. National Sustainable Development Strategies by the government is a good effort to achieve sustainability in all developmental activities specially GW resources of the country under one umbrella.
10. Global Best Management Practices on GW might work as guidelines for going into action for the GW management of the country.
If water is not managed properly, Days are coming when - possibilities of
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