Home Articles Assessing Agricultural Sustainability in Watersheds in India using Geomatics

Assessing Agricultural Sustainability in Watersheds in India using Geomatics

Dr. Kausalya Ramachandran
ICAR National Fellow,
Project Staff, CRIDA, Santoshnagar
Hyderabad – 500059, India
[email protected]

Dr. K.L.Sharma
ICAR National Fellow,
Project Staff, CRIDA, Santoshnagar
Hyderabad – 500059, India

T. Srinivas, M. Shankar Rao, M. Gayatri & V. Bhaskar

Abstract
In India watershed-based development has been the strategy for growth and sustainability of agriculture in the vast semi-arid and dry sub-humid regions popularly called rain-fed regions. Watershed Development Projects have been undertaken to enhance agricultural production, conserve natural resources base and ensure rural livelihood since 1980s. Initially soil and water conservation was the primary objective of the program which attracted large public investments in the last 25 years. Subsequently, egalitarian principles of equity and enhancing rural livelihood were given prominence; more recently the principle of sustainable development with emphasis on tenets of development economics like cost of degradation of fragile land and economic ecology like valuation of ecological services have gained emphasis. Large investments have been assigned for watershed based development in the National Five-Year Plans since 1990s and more investments have been earmarked till 2025.

The rain-fed regions of India span across several agro-climatic and ecological regions which warrant location-specific approaches to watershed development and management. Besides this three major ministries of the Govt. of India, development agencies and NGOs are involved in implementation of the projects. As a result, notwithstanding, the common guidelines for implementation, the projects have yielded little by way of lopsided development and impact assessment has been rendered impractical. In view of the huge investments already made and the necessity for effective implementation of watershed development projects in rain-fed areas of India, the tools of Geomatics were employed to evaluate the impact of various aspects of the program on agricultural sustainability, natural resource base and rural livelihood in selected villages. The present paper elucidates the multi-disciplinary approach of using satellite data, GPS and GIS along with conventional methods of field survey, transect walk, PRA, soil sampling and physico-chemical analysis and socio-economic survey for evaluation and monitoring these developmental activities for initiating corrective measures in order to increase their efficiency.

Introduction
Rain-fed agro-ecological regions (AER) which encompass the semi-arid tropics (SAT) and hot dry and moist sub-humid regions of India, extends over 76.74 M ha out of the total geog. area of 90.4 M ha in the states of Andhra Pradesh (AP), Maharashtra (MAHA), Karnataka (KAR) and Tamilnadu (TN) in Peninsular India. Watershed-based development has been an important component in the schemes for economic planning for development for ensuring agricultural productivity, natural resources management and enhancing rural livelihood. Over 71 million persons depend on agriculture and allied activities in these states alone according to 2001 Census of India (GoI,2001). Annual rainfall in this vast region ranges from 400 mm in the arid belt of Rayalseema in southern Andhra Pradesh to over 800 mm in the rest of the region which occur in 52 – 55 rainy days. Over 50 % of this rainfall which occurs in summer is associated with thunderstorm activity which lasts for a few hours. Considering such a rainfall pattern, rain – water harvesting, storing and prudent use for agriculture and other allied activities is of utmost importance.

Watershed Development Program was initiated in 1980s to address these limitations of the rain-fed agro-climatic and ecological niches of India (MoRD 1994; Hanumantha Rao 2000; Planning Commission, 2002, 2005). The emphasis and approach of the projects vary in consonance the ecological nuances of the regions. In scanty rainfall regions like in case of Maharastra uplands where annual rainfall is 500 mm, increasing irrigation potential by water harvesting and recharge of groundwater is given precedence. In case of Telengana region where annual rainfall is 800 mm and the terrain is gently undulating, water harvesting and surface storage in soil profile and farm ponds in preferred for enhancing productivity of rain-fed crops. In case of arid regions of Rayalseema where rainfall is scanty, water harvesting in field tanks for irrigation during crop stress, are preferred modes. The soil and water conservation structures (S&WC) viz., check-dam, stone weirs, contour bund, live bunds, vegetative cover, key-line plantation, grass way etc. are planned to provide impediments to overland runoff which induce soil erosion and deplete nutrients from agricultural fields. The structures are laid to guide runoff to designated farm ponds and tanks for water harvesting on surface besides impounding water for facilitating deep percolation for groundwater recharge. Also, soil degradation is a matter of grave concern in India which threatens agriculture. In Peninsular India over 47.3 M ha area have poor degraded soils (Saxena et al., 1999) of which 0.15 M ha have been categorized as wasteland (NRSA, 2000). More recently, the frequency of abnormal trends in climate like late onset of monsoon, early withdrawal, long inter-seasonal breaks, shift in peak rainfall period, cloud-burst, thunder storms, etc., are increasing leading to drought or flood occurrences. Thus, watershed development program (WSP) is undeniably, the most comprehensive program for achieving agricultural and ecological sustainability in the rain-fed regions of India.


Watershed Development Program (WDP) in India
A primary reason in favor of watershed-based development (WSD) in rain-fed region is the enormous cost of major water projects like the under-construction Narmada river-valley project. Hence the Govt. of India lays emphasis on augmenting water resources through small and decentralized projects like the watersheds. In India watershed projects have been undertaken under six major national programs, viz. Drought-Prone Area Program (DPAP), Desert Development Program (DDP), National Watershed Development Project for Rainfed Area (NWDPRA), Watershed Development in Shifting Cultivation Areas (WDSCA), Integrated Watershed Development Project (IWDP) and Employment Assurance Scheme (EAS) etc. by three Central Ministries of Govt. of India namely, Ministry of Rural Development (MoRD), Agriculture (MoA) and Environment & Forestry (MoEF). Significantly, 70% of funds for watershed development in the country are being spent under these six major programs. In 1999 a common approach was evolved for undertaking of WDP in India.

Several evaluation studies have been undertaken to assess the impact of WDP in rain-fed regions of India. Notable among them are by John Kerr & N. K. Sanghi (1992), John Kerr et al., (2002), Hanumantha Rao (2000) and Ratna Reddy et al. (2004). Most of these evaluation studies conducted till date, are based on econometric analysis as baseline information is often very difficult to obtain from the project implementing agency or the funding agency without which meaningful evaluation is impossible. The present study attempts to use tools of Geomatics in consonance with conventional techniques of field survey, soil and water analysis and socio-economic survey for creating baseline information of pre-project period and evaluation of post-project scenario.

Study area
The methodology was applied to evaluate watersheds developed in the Telengana region of AP which forms a part of the semi-arid and dry-sub-humid agro-ecological region of India (Velayutham et al, 1999). Five watersheds located in Telengana region in the districts of Rangareddy (RR) and Nalgonda were studied. The present paper describes the evaluation of WSD in one of the villages, Pamana in Chevella Mandal in RR district. While over 5000 ha area around Chevella township was developed as model watershed in 1985, Pamana village/ watershed (7807’30″E & 17016’45″N) was developed within Chevella Mandal under DPAP program in 1999. Under the WDP, ten check- dams were constructed in two micro-watersheds (MWS, catchment of first-order stream) in a planned manner (Fig.1).

The study of a treated and another untreated micro-watershed in Pamana provided interesting results. The village has a total area of 1010 ha with 300 farm households. Land holding size range from 0.5 – 4 ha although a majority of land holding size is lesser than 1 ha. A large majority of them are un-irrigated. Soil is essentially black belonging to Vertisols. Earlier, paddy cultivation was dominant wherever irrigation was available, however, with initiation of WDP, cash crops viz., cotton, tomato, carrot, coriander, onion, sugarcane, garlic and maize, besides flowers like Marigold, Jasmine, Chrysanthemums and Aster, have been introduced. In accordance with new guidelines for implementation of WSD in participatory mode, a Watershed Committee was formed in the village consisting of stakeholders (farmers belonging to the respective watersheds). Seed money was sanctioned to the village administration (Gram Panchayat) and the Department of Agriculture (DoA, AP Govt.) guided the villagers to identify and locate check-dams and other S&WC structures. The physical structures were built by the villagers under the guidance of engineers from the State Department of Govt. of AP, and payments were made from the DPAP fund. This was a two-pronged strategy under which the impact of drought was to be minimized by supporting farmers by providing livelihood during drought and ensuring agricultural productivity through S&WC on the long-run. The entire village has 19 micro-watersheds (MWS) of which 4 are treated with S&WC structures. For the present study we have taken one treated (TMWS) and another untreated micro-watershed (UTMWS). The TMWS selected for this study has an area of 129.49 ha. Over 40% of its area is irrigated, 51% un-irrigated where rainfed agriculture is practiced and the rest is scrubland with the ownership of Govt. The UTMW selected for the study covers an area of 21 ha with 23 % under irrigated agriculture and the rest under rainfed cultivation. The study of these two MWS has brought out interesting results.

Material & methods
Study was conducted in an integrated modular mode (Fig. 2) using Geomatics tools – GIS, GPS and Satellite data in addition to conventional techniques used in multi-disciplinary studies viz., field survey using toposheets, transact walk, civil survey using Total Station and GPS, soil survey, sampling and physico-chemical analysis in the lab, socio-economic survey using questionnaires and open-ended interviews with farmers, Participatory Rural Appraisal (PRA) at the village and collection of secondary data from mandal and district head quarters etc.

Watershed hierarchy was identified and mapped using ArcGIS (Ver. 9.0). The catchments of 1st order stream were nested into that of 2nd order stream catchments which in turn were nested into the 3rd order stream catchments and so forth. The National Watershed Atlas (AIS & LUS, 1988) classifies the entire drainage network of India in a hierarchical manner consisting of 5 stages, namely, water resource region, river basin, catchments, sub-catchments and watershed; we have delineated the 3rd, 2nd and 1st order streams and up-linked these to the national watershed hierarchy in earlier studies (Katyal et al., 1997; Kausalya Ramachandran et al., 2001; 2002). Watersheds in Pamana village were delineated in a similar fashion into sub-watersheds, mini- and micro-watersheds respectively. A treated or developed micro-watersheds (TMWS) where S&WC structures were located and one untreated micro-watersheds (UTMWS) where no interventions were made, were selected for evaluation. The nomenclature of the selected treated micro-watershed is as follows: TMW – 4D1E8a4c which stands for 4 – Southern Water Region, D – Krishna River, 1 – Musa River, E – Himayatsagar sub-catchment, 8 – Watershed No. (4th order stream catchments), a sub-watershed code (3rd order stream catchments), 4 mini-watershed (2nd order stream catchments) and c micro-watershed (1st order stream catchments).

Socio-economic survey was conducted using a structured questionnaire that was created to measure sustainability indicators. Two databases – one for watershed information and another for village information – were created in MS-Access and were linked to GIS platform. Soil and water sampling and analysis for 12 physico-chemical and biological parameters were undertaken and the results were input into Watershed Database. Satellite imagery of IRS 1D LISS-III of 16 Nov. 1998 (pre-project period), 17 March 2001, 16 Oct. 2004 and IRS – P6 data of 4 Nov. 2005 (post-project period) were digitally interpreted using ERDAS Imagine Ver. 9.0 and land use, cover and degradation maps were prepared (Fig. 3). The results were integrated for evaluation of WDP in Pamana.

Methodology for evaluation of WDP in Pamana
For evaluation of sustainability of WDP in Pamana village over 120 soils and water samples were collected and analysed for assessing soil fertility status and water quality. Over 180 farm households were interviewed and a socio-economic analysis was carried out using structured questionnaires to generate baseline information for testing the relevant sustainability indicator. Forty eight sustainability indicators were assessed for 8 issues at 5 levels of analysis as indicated below (Table 1).

Table.1: List of sustainability indicators used for evaluation of WDP

Suitable indicators were selected for assessing the five tenets of sustainability (FAO, 1993, Smyth et al., 1993; 1995, Gomez et al., 1996 & Swete Kelley et al. 1998). For instance, to assess sustainability of agricultural productivity, crop yield was used as an indicator. To evaluate security of livelihood operations, factors which would impact agricultural production systems viz., soil cover, yield variability and rainfall distribution, were to be analysed. For environmental protection, soil quality/ quantity, water quality/ quantity, biodiversity, etc., were to be evaluated. In order to ascertain viability of agricultural operations, net farm profitability, input-use efficiency, off-farm income and economic return were to be studied. To ascertain whether WDP and its components of development strategy were acceptable, types of conservation practices prevalent and adopted by farmers, method of Land Use Planning and decision – making criteria of farmers, were to be analysed.

Significantly, the methodology enabled the quantification of several aspects associated with land management in developed / treated watersheds, viz., new land management practices introduced and adopted, changes in cropping pattern and replacement of traditional cropping system with cash crops, availability of credit facility from Rural Co-operative Banks or credit society and support from institutions like Agricultural Extension Department etc., which could all ensure agricultural sustainability. A Principal Component Analysis (PCA) was attempted on the set of sustainability indicators selected for the study. Sustainability indicators pertaining to three aspects i.e., Farmers’ Satisfaction, Resource Conservation and Watershed Management were used for assessing agricultural sustainability in the selected watershed under the present study.

Data generated under various modules of the project were correlated with the list of sustainability indicators chosen for the purpose. A matrix was evolved and averages, threshold values and indices for each of the indicator were generated adapting the method indicated by Gomez et al., (1996). Some of the indicators produced qualitative information which was numerically calibrated for easy comprehension, comparison and removal of ambiguity according to the weight-age presented in Table 2. For instance, under the issue of resource availability where deforestation rate could be numerically estimated using satellite data of various time-period, availability of fuel wood or fodder could be assessed only qualitatively. Hence scores were generated to depict the status of sustainability. A final scorecard was generated to indicate how various components of WDP had faired in the MWS in Pamana; which components were strong, which were the weak links that could make the WDP unsustainable. Cob – web diagrams used by Gomez et al., (1996) were found appropriate to draw attention to the strength and weaknesses of the WDP undertaken in Pamana.

Table 2: Sustainability Indicators for a TWMS

Results & Discussion
The issue of sustainability of rainfed agriculture was analysed using a wide range of indicators which included a few indicators that can be deduced from satellite data and analysed using GIS. While the viability of WDP was assessed using indicators pertaining to Farmer’s Satisfaction, Resource Conservation and activities initiated under Watershed Development program, as indicated through cob-web diagrams (figs. 4 & 5); use of satellite data and GIS for study of aspects of LUCC (fig. 6) and NDVI (fig. 7) have been discussed here. The issue of equity was also analysed for the TMWS & UTMWS in the study area. It was found that equity was better addressed in TMWS (0.36) which is slightly poorer than the national average for India (0.30 – 0.34) while in UTMWS (0.47) the inequality among farmers was severe (Fig. 8).

Land Use Cover Change (LUCC) analysis
In order to study the impact of sustainability of WDP satellite imagery of the study area (IRS LISS-III- 1D Path -Row 100-60) of pre-WS period (16 Nov. 1998) and Post-WS period (IRS P6 of 4 Nov. 2005) were classified using ERDAS Imagine Ver. 9.0. Figure 6 indicates the trend in change of land use and land cover in the two MWS. While agricultural area is largely stabilized in the TMWS there is a large expansion of agricultural activity in marginal lands belonging to LCC IV and V with slope of 4 -5 % that would induce soil erosion (Fig.9). Land fallow which is essential for rejuvenation of land is being maintained in the TMWS, while there is no fallowing practiced in UTMWS. Tree groves have been depleted in UTMWS and vegetative cover from scrublands have also decreased which would adversely affect soil OC content. All these trends indicate unsustainable trend in UTMWS.

Normalized Difference Vegetation Index (NDVI)
Light reflectance from vegetation was compared in the post-kharif season period in 1998 and 2005. NDVI was calculated using the formulae IR-IR/IR+IR where IR stands for infrared and R stands for red portion of the EM spectrum. The Vegetation Index (VI) was normalized for topographic effect and the difference of NDVI in the study area in pre- and post-watershed project period is indicated in Fig. 7. Evidently in pre-watershed period, NDVI in both TMWS and UTMWS was lower. In 2005, NDVI was higher in large parts of TMWS which indicates better rabi-crop stand. Higher NDVI was also recorded in UTMWS in Nov. 2005 which is indicative of good vegetation stand.

Conclusion
WDP is essential for development of rain fed agriculture in India as it would ensure agricultural production through natural resource conservation viz., water harvesting and halting of soil erosion. Although WDP was initiated by Govt. of India in 1985 with massive public investment, not all projects are yielding sustainable agricultural growth as indicated by our methodology.

The merit of this method for evaluation lies in the fact that it derives data and information heavily from Geomatics and uses them successfully to identify the strengths and weakness of the WDP in an area. The methodology permits temporal analysis of indicators, comparison of various WDP across AER and at different periods of time. Most importantly, it helps identify weak linkages in a given WDP which can be corrected to achieve agricultural sustainability in rain fed areas.

Acknowledgement:
Authors thank the Indian Council of Agriculture Research (ICAR) for awarding and funding of research under National Fellowship Scheme to the first author. They appreciate the constant encouragement provided by Director, Central Research Institute for Dryland Agriculture (CRIDA), Hyderabad, during this study.

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