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

Thanks