SPATIAL DECISION SUPPORT SYSTEM FOR RURAL LAND USE PLANNING

Transcription

1 SPATIAL DECISION SUPPORT SYSTEM FOR RURAL LAND USE PLANNING J. ADINARAYANA, S. MAITRA, G. VENKATARAMAN Centre of Studies in Resources Engineering Indian Institute of Technology Bombay, Powai, Mumbai adi@csre.iitb.ac.in ABSTRACT A prototype decision support system is developed for district-level user community for taking decisions on watershed-based rural land use planning. This decision support research helps in (1) identifying the critical areas for government-sponsored watershed management schemes based on physical and socio-economic indicators; and (2) suitable zones for constructing small-scale water resources infrastructure. A simple and robust procedure/framework for land evaluation for changes in land use, based on wellestablished principles/criteria, is presented in the model. BACKGROUND District/sub-district level planning, with emphasis on conservation management of critical rural watersheds, has been stressed for many years in successive National Development Plans in India. The established procedure for rural development planning in India remains top-down by way schemes to address specific problems and opportunities. Each scheme has a set of policies that are defined by legislation. Under these watershed management schemes, planners at district/sub-district level need to identify the critical watersheds/sub-watersheds for preferential treatments/land use plans. This decision support research, called Spatial Decision Support System for rural Land Use Planning SDSS/LUP, is an attempt towards an executive-level land use planning, i.e. where the decisions must be made on the use and allocation of resources on watershed basis by the responsible agencies. DECISIONS TO SUPPORT At the outset, a needs assessment was carried out amongst district-level staff to establish their requirements for spatial data. It proved difficult for them to articulate their needs but a number of specific requirements emerged from these discussions: Decision type A: Area selection for schemes A.1 Which are priority watersheds for intervention by various user departments? A.1.1 Within a priority watershed, which sub-watersheds should be treated first? 233

2 A.2 Where, within a sub-watershed, are the hotspots requiring interventions? Decision type B: Site selection for infrastructure B.1 Where should small-scale conservation infrastructure be built? B.2 Where should water resources infrastructure be built or authorized? Decision type C: Land evaluation for changes in land use (Adinarayana et al., 2000) C.1 Land use options which will yield immediate benefit to the land user (economic options) C.2 Land use changes which may yield economic benefits only over the longer term but which increase the sustainability of the land use system (conservation options) C.3 Changes of practice that can be accommodated easily within the existing farming system (easily implementable options) C.4 Land Use options that require a major change in the farming system, or resources or technology not available to the land user (radical options) In the first instance, emphasis is given on selecting priority sites for conservation planning schemes that will help the decision-maker to do their job more easily, accurately and consistently. Each scheme is bounded by government policies, which have social, economic and biophysical dimensions. Policy is enshrined in the directives that establish the scheme and these commonly lay down criteria for site selection. For example, the National Watershed Development Programme for Rainfed Agriculture (NWDPRA) lays down four criteria: <30% area is irrigated; <750mm average rainfall; no other schemes have been implemented; and size of a watershed for this scheme is ha. Within any NWDPRA watershed there will be some 20 sub-watersheds, each of 500ha, that may be considered the primary planning units because they are small enough for concerted intervention. They must be ranked in order of priority for intervention, and this may be done in various ways. The SDSS adopts explicit criteria: Degree to which sub-watershed satisfies the objectives of a particular scheme including physical as well as social indicators; Actual problems with productivity due to erosion or other degradation processes (onsite effects); Actual sediment delivery to reservoirs (off-site or downstream effects); Actual extent of degraded land; Multi-criteria evaluation based on all of the above. A separate procedure is required for each of these criteria, and then a multi-criteria analysis can be used to combine them. Or, decision-makers may simply compare the several results and combine them intuitively. 234

3 TEST AREA AND USER INTERFACE In order to test and validate the concepts of SDSS/LUP, two talukas (blocks) were selected: Chikballapur and Gudibanda for identifying the priority watersheds for NWDPRA scheme. For others, i.e. sub-watershed prioritization and site selection for infrastructures, the Ramapatna watershed (about 1600 ha) in the district was selected. The SDSS must present a simple, intuitive interface to the user, who is presumed to be somewhat a novice to the use of a GIS. The interface displays a series of maps, complete with symbols and attributes, called themes. These may be collected in views, each having a table of contents showing the themes. The user chooses which themes to view by highlighting a check box. Simple tools enable the user to zoom in and out, and to obtain information on map areas and other details specific to each map delineation. The SDSS/LUP is presented as a series of views: (1) input maps and tables; (2) derived maps; (3) ratings that can be called upon by the user. PROTOTYPE A prototype modeling on selecting the priority watersheds for different schemes was examined with the following models/criteria: Watershed prioritization - NWDPRA criteria. Sub-watershed prioritization on the basis of relative soil erosion intensity - Morgan s model (Morgan et al., 1982 and 1984) using Biophysical land units (BPLUs) as the strategic natural unit. Identifying the critical sectors/hot-spots/bplus (highly erodable areas) within the sub-watershed - - Morgan s model Sub-watershed prioritization on the basis of sediment delivery to the active stream/water-body - Sediment Yield Index (SYI) model (AISLUS, 1991). Sub-watershed prioritization on the basis of extent of degraded lands delineated from remotely sensed data (IRS 1C-PAN). Integrated Mission for Sustainable Development (IMSD, 1995) criteria for identifying suitable zones for percolation tanks in a watershed. Priority ratings of watersheds and sub-watersheds for taking decision on the basis of above scenarios are depicted in Table 1. The district/taluka officials involved in the watershed management programmes can choose the above watersheds/sub-watersheds depending on the scheme based on the above physical/socio-economic problems. Suitable areas for constructing percolation tanks in Ramapatna watershed was carried out using the IMSD criteria. However, the exact location of this water resource infrastructure is possible only after the field investigations/verifications. 235

4 Land evaluation for changes in land use This is a complex task than those dealt so far. A better service can be provided with regard to the land evaluation for conservation and management options and for suggesting new land use types. We are exploring the possibility of utilizing the TIM (Threat Identification and Management) concept outlined by Smith et al. (1999) in which the system provides spatial information on various threats to the suitability of land use types. With this information, district officers will be in a position to design land use systems that can contain the threats. The simple modeling capability of SDSS will be able to test the applicability of innovative approach. A cut-down version of the Automated Land Evaluation Systems (ALES), suggested by Rossiter & van Wambeke (1997), can be bolted on to the SDSS/LUP to provide land suitability evaluation for specific crops and land use types; including basic financial/economic analysis The outcome of this decision support research, with extensive local stakeholders involvement, would possibly become an important tool to solve some of the existing poorly structured problems with a spatial dimension that a rural land planner may ask. Particularly, SDSS/LUP helps the users/clients in the districts to investigate the trade-off in selecting watersheds/sub-watersheds on a priority basis for different schemes under conservation/watershed management sector, which are based on physical/social indicators. The methodology is designed to be applied to any part of India, although the prototype SDSS/LUP is specific to the test area. ACKNOWLEDGEMENTS SDSS/LUP forms a part of the UNDP/DST joint effort GIS based Technologies for Local Level Development Planning (IND/95/002), and was supported under the DST Scheme : Natural Resources Data Management Systems (NRDMS). Authors wish to thank the UNDP Consultants Dr David G. Rossiter, ITC-Enschede, and Dr David Dent, Bureau of Rural Sciences, Australia for their valuable guidance and suggestions on the approach. REFERENCES Adinarayana, J., Maitra, S. and Dent, D.L. (2000). Development of a spatial decision support system for land use planning at district level in India, The Land, 4.2 : AISLUS (1991). Methodology of priority delineation survey. All India Soil and Land Use Survey, Department of Agriculture & Co-operation, Ministry of Agriculture, Government of India. New Delhi. Integrated Mission for Sustainable Development (1995), Technical Guidelines, National Remote Sensing Agency, Department of Space, India. 236

5 Morgan, R.P.C., Hatch, T and Wan Suleiman, Wan Harun (1982). A simple procedure for assessing soil erosion risk : a case study for Malaysia. Zeitschrift fur Geomorphologie N.F. Suppl-Bd. 44: Morgan, R. P. C., Morgan, D. D. V. and Finney, H.J. (1984). A predictive model for the assessment of soil erosion risk. Journal of Agricultural Engineering Research 30: Reprinted as pp in: Morgan, R. P. C. (ed.) Soil erosion and its control. New York, Van Nostrand Reinhold. Rossiter D.G. and van Wambeke, A. (1997). ALES Version 4, Users Manual. SCAC Teaching Series T93-2. Soil, Crop and Atmospheric Sciences Department, Cornell University, Ithaca NY. Smith C., Thwaites, R. and McDonald, G. (1999). TIM : evaluating the sustainability of agricultural land management at the planning stage. The Land, 3.1:

6 Table 1. Scenarios / multi-criteria evaluation for watershed/sub-watershed selection Physical Characteristics Priority ratings SOCIO-ECONOMIC CHARACTERISTICS NWDPRA WATERSHED Bairasagara 1 2 Chalamena Halli 4 3 Chonduru 3 1 Peresandra 2 4 Sub-watershed Priority ratings Soil intensity erosion Sediment Index Yield Extent of degraded lands RP_E RP_N RP_W