A project Report on Use of Remote Sensing and GIS to Assess the Rainwater Harvesting Potential in Behror & Neemrana Block, Rajasthan

Transcription

1 A project Report on Use of Remote Sensing and GIS to Assess the Rainwater Harvesting Potential in Behror & Neemrana Block, Rajasthan

2 Use of Remote Sensing and GIS to Assess the Rainwater Harvesting Potential in Behror Tehsil, Rajasthan By Ekta Gupta A project report submitted to Dr. Parul Srivastava, Professor at NIIT University in partial fulfillment of the requirements for degree of M.Tech in GIS. NIIT University, Neemrana Rajasthan

3 Acknowledgements I am grateful to the Dr. Parul Srivastava for her valuable suggestion that has given me immense support to ensure that my work conforms to the set standards. I also do wish to extend my sincere gratitude to the NIIT University for arranging vehicle for my field survey. I thank to Arbind Anand, Ajit Babar, Shubhangi Mane and Srimoyee Dutta for extending their support and help to me at all phases of my project completion. Ekta Gupta

4 1 Contents 2 Introduction Rain Water Harvesting (RWH) Concept Application of Remote Sensing & GIS in RWH Problem Identification Objective Study Area Climate Topographical and Hydrogeological Settings Man-Environment Relationship Soil Characteristics Material and Methodology Material Used Software Used Dataset Used Methodology Rainfall Data Interpolation Thematic Maps Generation DEM Hydro-Processing Calculation of Rain Water Harvesting Potential (RWHP) Decision Making and RWH Site Selection Results and Discussion Rain Water Harvesting Potential Map Suitable sites for Rain Water Harvesting Conclusion... 31

5 List of Figures Figure 4-1 Study Area Map Figure 5-1 Methodology Flow Chart Figure 5-2 Average Annual Rainfall Figure 5-4 Land Use/Land Cover Map Figure 5-3 Soil Texture Map Figure 5-5 Classified Slope Map Figure 5-6Strahler Drainage Order Map Figure 5-7 Runoff Coefficient Map Figure 5-8 Rain Water Harvesting Potential Map Figure 10 Suitable Sites for Farm Ponds Figure 11 Suitable Sites for Percolation Tanks Figure 12 Suitable Sites for Check Dams... 30

6 List of Tables Table 5-1The descriptive characteristics of the SCS soil groups based on infiltration rates Table 5-2 Rational Method Runoff Coefficient Table 5-3 Suitable area for different RWH Structures... 26

7 Abbreviations RWH: RWE: Rain Water Harvesting Rain Water Endowment RWHP: Rain Water Harvesting Potential SCS: HSG: Soil Conservation Service Hydrological Soil Group

8 Abstract This study presents a methodology that is used to identify Rain Water Harvesting (RWH) sites using GIS and Remote Sensing product in Behror d Neemrana Tehsil which belongs to the semi arid zone and is likely to face water deficiency in the near future as new settlements are coming up due to industrialization and urbanization in this area. Input layers that are used in this study includes rainfall map, slope, land use/cover map, Soil map and stream order map. ArcGIS 10.1 and ERDAS Imagine 11 have been used to derive all these required key spatial parameters. Runoff Modeling is done using Soil Conservation Services (SCS) hydrological soil groups and rational method of runoff coefficient. For the assignment of weights to each factor and site suitability analysis weighted overlay method in ArcGIS 10.1 is used. The obtained results have revealed that the study area has plenty of scope for the development of Water Harvesting Structures. The total Rain Water Harvesting Potential of the study area is 41,23,356 cubic meters which are sufficient to feed on the ever increasing demand on water if harvest and conserve properly. Produced suitability map can be refered for the selection of harvesting sites.

9 Summary The present study has identified the application of GIS and Remote Sensing product for the selection of suitable Rain Water Harvesting (RWH) sites along with the total RWH potential of Behror d Neemrana Tehsil which belongs to the semi arid zone and is likely to face water deficiency in the near future as new settlements are coming up due to industrialization and urbanization in this area. Input layers that are used in this study includes slope, land use/cover map, Soil map and stream order map. ArcGIS 10.1 and Erdas Imagine 11 have been usedto derive all these key spatial layers. Runoff Modeling is done usingsoil Conservation Services (SCS) hydrological soil groups and method. For the assignment of weights to each factor weighted overlay method in ArcGIS 10.1 is used. The obtained results have revealed that the study area has plenty of scope for the development of Water Harvesting Structures.The total Rain Water Harvesting Potential of the study area is 41,23,356 cubic meters which are sufficient to feed on the ever increasing demand on water if harvest and conserve properly.. Out of the total area of 727 km 2 ;187.3 km 2, 194.5km 2 & 187.3km 2 area is suitable for Check Dam, Percolation Tank and Farm Pond respectively. Produced suitability map will help in the selection of the suitable location of harvesting structures and hence, help in water conservation in a water depleted area.

10 2 Introduction Water is the most crucial for maintaining an environment and ecosystem conducive to sustaining all forms of life. It plays a vital role not only in fulfilling basic human need for life and health but in socio-economic development also.it is essential to conserve and manage this limited and precious resource. As the primary source of water is rainfall, so it becomes necessary for us to harvest it effectively we can maximize the storage and minimize the wastage of rain water. 2.1 Rain Water Harvesting (RWH) Concept Rain Water Harvesting and Conservation, is the activity of direct collection of rain water collected can be stored for direct use or can be re-charged into the Ground Water. The main goal is to minimize flow of Rain Water through Drains/Nallahas to the rivers without making any use of the same. It is a known fact that the Ground Water level is depleting and going down and down in the last decades. Thus Rain Water Harvesting & Conservation aims at optimum utilization of the natural resource, that is, Rain Water, which is the first form of water that we know in the hydrological cycle and hence is a primary source of water for us. The Rivers, Lakes and Ground Water harvesting and conservation, we depend entirely on such secondary sources of water and in the process it is forgotten that rain is the ultimate source that rain is the ultimate source that feeds to these secondary sources. The value of this important primary source of water must not be lost. Rain Water Harvesting & Conservation means to understand the value of rain and to make optimum use of Rain Water at the place where it falls(1). 2.2 Application of Remote Sensing & GIS in RWH Several studies have revealed that Remote Sensing Data and GIS tools are very helpful in determining the potential sites for Water Harvesting. Padmavathy et al., 1993,(2) have used Arc/Info for the derivation of various thematic maps such as a soil map, a land use map, a contour map, a lineament and fracture map as well as a drainage map of an area selected from IRS-1A imagery and Survey of India (SOI) topographic map sheets. "Check dam sites" were selected according to a suitability ranking considering certain criteria without estimating runoff. Gupta et al. 1997, (3) in their study, have identified the capability of GIS and Remote Sensing in runoff estimation. Decision making and planning about the required number and

11 type of water harvesting structure to be constructed using RS and GIS in the watershed is extremely important to avoid mammoth investments on unproductive structures(2). 2.3 Problem Identification According to DEA Report Alwar, area around Neemrana exhibit steep depletion of water level ranging from 7m to 10m during the period of (3). Moreover, according to National Capital Region Planning Board (NCRPB) s(4) report on water resource in NCR, Behror Block belongs to over-exploitation category. Availability of water in near future is going to become a matter of grave concern as Shahajanpur-Neemrana-Behror (SNB) complex and 129 villages along NH-8 in Rajasthan sub-region of NCR was identified as a suitable area for Global City Project by Government of Rajasthan and hence, is being developed at an unprecedented rate. This will increase demand and pressure on already depleting water resource many folds. Studies need to be conducted for identification of catchment areas with good storage recharge potential and ground water aquifers with goodretention and community level projects be developed & implemented, so that sustainability of water resource can be assured.

12 3 Objective The main objective of the present study is to assess the Rain Water Harvesting Potential of the study area. To assess the Road Water Harvesting Potential To identify and map out the potential Water harvesting Sites through site suitability analysis in RS and GIS environment. To suggest the suitable Rain Water Harvesting Practice in the study area

13 4 Study Area Study area is located in north-western corner of Alwar district, Rajasthan, covering two Tehsil viz. Neemrana and Behror. It extends between 28 11'22"N to 27 47'57"N latitude and 76 8'48"E to 76 31'12" E longitude. It covers an area of sq km and accommodates 3, 05,688 people. Study Area Map Landsat8, 2013 image (FCC) Figure 4-1 Study Area Map 4.1 Climate The climate of the study area is semi-arid and very hot in summer and extremely cold in winter. The monsoon season is of very short duration. The cold season starts by the middle of November and continues up to the beginning of March. The summer season follows thereafter and extends up to the end of the June. The south west monsoon continues from July to mid- September. The period from mid-september to mid-november forms the post-monsoon

14 season. The rainfall during the south-west monsoons constitutes about 80 % of the annual rainfall. 620 mm is the annual average rainfall. 4.2 Topographical and Hydrogeological Settings The Aravalli mountain range (one of the oldest in the world) in western India runs approximately 482 km from northeast to southwest across the State of Rajasthan. The study area has an average elevation of 312 m and land slope is less than 10 m per km. Most of the area is covered with Alluvial Plain of Fluvial origin and Sandy Plain of Aeolian origin. There are some patches of Ravinated pediments(5). 4.3 Man-Environment Relationship Until the 1930s and 1940s, the Aravalli range had verdant forest cover. A multitude of traditional water-harvesting systems ensured that the low rainfall was optimally utilized to provide an adequate water supply to the village community throughout the year. However, due to large-scale logging in later years, surface runoff increased every year, resulting in considerable depletion of groundwater recharge. The complete transfer of water management from community to government created a cycle of neglect and scorn for timetested traditions and a dependency-syndrome among the village community. The synergy between humankind and nature that was the legacy of centuries of tradition was destroyed in a matter of decades. Drought became a recurring and grim reality in the region (6). 4.4 Soil Characteristics Study area has mainly four types of soil. Red gravelly soil has characteristic of excellent drainage(7); soils of Aravalli Hills are moderately deep undifferentiated soils and rocky land of Aravallis subjected to high run off and severely eroded; soil of Aravalli Pediment are very deep, well-drained soils with gentle slope, coarse loamy soils with loamy surface, severely eroded and slightly saline; soil of Old Alluvial Plain are moderately drained, fine loamy, calcareous soils with loamy surface, low fertility status, low moisture retention capacity, moderately eroded(8).

15 5 Material and Methodology 5.1 Material Used Software Used Erdas Imagine-11has been used for mosaicing and image classification. ArcGIS Desktop10.1 for Vector and Raster based analysis such as Map Overlay, Proximity Analysis, Local and Zonal Function, Rainfall Interpolation, and for generating Flow Accumulation map, Raster Stream Network and Stream Order map. Google Earth has been used for digitizing settlements, water body, pediments and hills Dataset Used Landsat 8 image, May 2013; band 3, 4, 5; resolution 30m. ASTER DEM, resolution 30m. Soil Map of Alwar (Source: NATMO) Hydrogeological Map (Source: / Rainfall Data of 37 years ( ) (source: India Water Portal) Field data has been generated using GPS for ground truth

16 5.2 Methodology The methodology used in the present study has been summarized in the flow chart below Conceptual Framework Figure 5-1 Methodology Flow Chart Rainfall Data Interpolation Study area has only 3 rainfall gauging stations. A dense network is required to estimate accurately spatial distribution of rainfall of a given area. Therefore, 16 stations in Alwar district are used for interpolation on the entire district and then interpolated rainfall map of the study area was clipped. The interpolation has been done in ArcGIS 10.1 using Inverse Distance Weight (IDW). Inverse distance weighted (IDW) interpolation determines cell values using a linearly weighted combination of a set of sample points. The weight is a function of inverse distance (ArcGIS

17 10.1 Help).The interpolated raster map shows decrease pattern in Average Annual Rainfall from north to south, seefigure 5-2. Figure 5-2 Average Annual Rainfall

18 5.2.2 Thematic Maps Generation Land Use Land Cover (LULC) Map Landsat 8, May, 2013, imagery is used for LULC classification. Since the study area has been covered by two imageries, therefore, images were mosaicked first and Supervised Classification tool was run in Erdas Imagine 10. Parallelepiped and Maximum Likelihood decision rule ware selected as non-parametric and parametric decision rule respectively. The resulted imagery was recoded further using vector files that were digitized using Google Earth. There are total seven classes, these are settlement, agriculture field, road, quarry, waterbody, mixed shrubs and mixed vegetation, seefigure Soil Map The study area lacks an elaborate soil map. The soil map of the study area was digitized from Alwar district soil map of 1: 100,000 scale. Further improvements were carried out with the help of literature, seefigure Slope Map The slope of a given area influences recharge and infiltration hence the amount of runoff that is expected from the terrain. Technology suitability for different RWH options highly depends on the slope of a given area (9). Slope map was derived from 30 m resolution ASTER DEM. Firstly, ASTER DEM image was processed to remove peaks and sinks using ArcGIS and then converted into Slope Map in percentage. In this study two different classified slope maps was required. The first one is classified on the basis of slope suitability criteria for various water harvesting structures. It is classified into four categories; these are, 0-3, 3-5, 5-15 and >15 see Figure 5-1. The other one is for calculating Runoff Coefficient on the basis of Error! Reference source not found..

19 5.2.3 DEM Hydro-Processing DEM Hydro-Processing involves extraction of drainage parameters from DEM. In the present study following hydrological parameters have been extracted from Hydrological tools of ArcGIS Flow Accumulation Raster The result of Flow Accumulation is a raster of accumulated flow to each cell, as determined by accumulating the weight for all cells that flow into each downslope cell. It is used to generate stream raster, which is required as an input to create Stream Order Raster Flow Direction Raster Flow Direction tool creates a raster of flow direction from each cell to its steepest downslope neighbor. It is also required as an input to create Stream Order Raster Stream Raster Stream Raster requires a threshold value. For the present study threshold value of 500 has been taken. Cells that have more than 500 cells flowing into them are used to define the stream network. Con tool has been used to create a stream network raster where flow accumulation values of 500 or greater go to one, and the remainder are put to the background (NoData) Strahler Stream Order The method of stream ordering was proposed by Strahler in Stream order only increases when streams of the same order intersect. Stream Order Raster was generated using Stream Order tool see Figure 5-6.

20 Figure 5-4 Land Use/Land Cover Map Figure 5-3 Soil Texture Map Figure 5-5 Classified Slope Map Figure 5-6Strahler Drainage Order Map

21 5.2.4 Calculation of Rain Water Harvesting Potential (RWHP) The total amount of water i.e. received in the form of rainfall over an area is called the Rain Water Endowment (RWE) of that area. Out of this the amount that can be effectively harvested called the Rain Water Harvesting Potential (1). Rain Water Harvested Potential (RWHP) = Rainfall Endowment of the area X Runoff Coefficient X 0.8 (constant coefficient 1 ) (i) RWE: It was calculated for each pixel by multiplying pixel area with the interpolated rainfall value (in meter) of that pixel. Runoff Coefficient:The method used to calculate runoff coefficient is Rational Method. The major factors affecting the rational method runoff coefficient value for a watershed are the land use, the soil type and the slope of the watershed. The physical interpretation of the runoff coefficient for a watershed is the fraction of rainfall on that watershed that becomes storm water runoff. Thus the runoff coefficient must have a value between zero and one (10). Land Use:Surfaces that are relatively impervious like streets and parking lots have runoff coefficients approaching one. Surfaces with vegetation to intercept surface runoff and those that allow infiltration of rainfall have lower runoff coefficients. Slope: All other things being equal, a watershed with a greater slope will have more storm water runoff and thus a higher runoff coefficient than a watershed with a lower slope. Soil Type: Soils that have a high clay content don't allow very much infiltration and thus have relatively high runoff coefficients, while soils with high sand content have higher infiltration rates and low runoff coefficients. The U.S. Soil Conservation Service (SCS) has four soil group identifications that provide information helpful in determining watershed runoff coefficients. The four soil groups are identified as A, B, C, and D. Classification of a given soil into one of these SCS groups can be on the basis of a description of the soil characteristics or on the basis of a measured minimum infiltration rate for the soil. The descriptive characteristics of the four SCS soil groups are summarized in the listerror! Reference source not found.:

22 Table 5-1The descriptive characteristics of the four SCS soil groups based on infiltration rates (9). Sr. No. Hydrologic Soil Group Description 1 Group A Have a low runoff potential due to high infiltration rates. These soils consist primarily of deep, well-drained sands and gravels. 2 Group B Have a moderately low runoff potential due to moderate infiltration rates. These soils consist primarily of moderately deep to deep, moderately well- to well-drained soils with moderately fine to moderately coarse textures. 3 Group C Have a moderately high runoff potential due to slow infiltration rates. These soils consist primarily of soils in which a layer exists near the surface that impedes the downward movement of water or soils with moderately fine to fine texture. 4 Group D Have a high runoff potential due to very slow infiltration rates. These soils consist primarily of clays with high swelling potential, soils with permanently high water tables, The study area has Hydrologic Soil Group (HSG) A (Red Gravelly Soil), HSG B (Old Alluvial Plain & Aravalli Pediment) &HSG D (Aravalli Hill Soil). This categorization has been done by referring many papers on study area and on soil characteristics (8) (11). In the present study, Table 5-2 is used. This table contains Runoff Coefficient value for different landuse, watershed slopes and SCS based Hydrological Soil Groups. Group C is not found in the study area, hence, not included in the table. A Runoff Coefficient raster has been created by combining thematic layer of HSG Map, Slope Map and LULC Map and then assigning respective values given in the Table 5-2. By putting this raster layer and RWE raster layer into equation 1, Rain Water Harvesting Potential Map has been generated and thetotal potential has been calculated (see Figure 5-1).

23 Table 5-2 Rational Method Runoff Coefficient (12) Slope <2% 2-6% >6% <2% 2-6% >6% <2% 2-6% >6% LULC classes Soil Group A Soil Group A Soil Group A Mixed Shrub Mixed Vegetation Settlement Agriculture Quarry Road Figure 5-7 Runoff Coefficient Map 1 Runoff coefficient for mixed vegetation has been taken as an average of Forest and Pasture. 2 Runoff coefficient for settlement has been taken as an average of all the landuse belong to the settlement. 3 Runoff coefficient for quarry has been taken as an average of disturbed area and street.

24 5.2.5 Decision Making and RWH Site Selection Criteria Selection To find out suitable sites for Check dams, Percolation tank, farm pond following criteria is used (13; 1). 1. Percolation Tank A tank can be located either across small streams by creating low elevation. Terrain with highly fractured and weathered rock for speedy recharge. Submergence area should be uncultivated as far as possible. Soils in the catchment area should preferably be of light sandy type to avoid silting up of the tank bed. The location of the tank should preferably be downstream of runoff zone or in the upper part of the transition zone, with a land slope gradient of 3 to 5%. 2. Farm Pond In relatively flatter terrain with good soil cover, a farm pond has an earth section with usually 3:1 side slopes onwaterside and 2:1 side slopes on the downstream face. The drainage area above the pond should be large enough to fill the pond in 2 or 3 spells of good rainfall. The pond should be located where it could serve a major purpose: e.g. for irrigation, it should be above the irrigated fields and for sediment control it should intercept the flow from the most erodible parts of the catchment. Junction of two drainage channels or large natural depressions should be preferred. The land surface should not have excessive seepage losses unless it is meant to serve as a percolation tank for ground water recharge. 3. Check Dam Rainfall: mm; from arid to semi-arid areas. Soils: all agricultural soils - poorer soils will be improved by treatment. Slopes: best below 2% for most effective water spreading.

25 Weight Assignment and Overlay Four thematic raster layers were overlaid using Weighted Overlay Tool in ArcGIS This tool multiplies each raster layers by their given weight and sums the multiplied value of all layers. The individual categories within each layer were given weight on the basis of suitability criteria. Evaluation scale was set in a range of 1 to 5 with equal reference to all layers.

26 5.3 Results and Discussion Rain Water Harvesting Potential Map RWHP map (seefigure 5-8)is created by the weighted overlay operation. Total calculated RWHP of the study area is 41,23,356 cubic meter. Total Rainwater Endowment of the study area is 49,28,319 cubic meter Suitable sites for Rain Water Harvesting The derived suitable sites for farm pond, percolation tank and check dam are shown in figurefigure 9, Figure 10&Figure 11 respectively. 5-3 Table showing suitable area for different RWH Structures RWH Structures Area (square kilometers) Suitaible Most Suitable Total Farm Pond Percolation Tank Check Dam

27 Figure 5-8 Rain Water Harvesting Potential Map

28 Figure 9 Suitable Sites for Farm Ponds

29 Figure 10 Suitable Sites for Percolation Tanks

30 Figure 11 Suitable Sites for Check Dams

31 6 Conclusion Due to rapid urbanization and industrialization in the study area, demand for water consumption has increased at an unprecedented rate. Statistics on water availability in the study area has already revealed that water table has gone down remarkably in last 2-3 decades. Nevertheless, the area has sufficient potential to feed on the ever increasing demand of water if harvest and conserve properly. Site selection for RWH is carried out by overlying the slope, soil, landuse/land cover & buffered stream order maps. The study area is having full scope for percolation tanks, farm ponds and check dams. Produced map will help in the selection of the suitable location of harvesting structures and hence, help in water conservation in a water depleted area.

32 References 1. CPWD, govt. of India.Manual on Rain Water Harvesting and Conservation. Chapter 1, Selection of Suitable Sites for Water Harvesting Structures in Soankhad Water, Punjab using Remote Sensing and Geographical Information System (RS & GIS) Approach- A Case Study. Litoria P.K., Singh D., Singh J.P. (2009). J.Indian Soc. Remote Sens., 37:21-35; retrieved on 2nd Nov,2013, from 3. ANON, 2009,.District Environment Atlas, Alwar. : Rajasthan State Pollution Control Board, Jaipur; Central Pollution Control Board, New Delhi & Development Alternatives, New Delhi. 4. Regional Plan 2021, National Capital Region Planning Board.Chapter 8. : retrieved on October 12th, 2013, from 5. Retrieved on 16th Oct, 2013 from 6. Kishore, A. (2003).Taking control of their lives. : Ecologist Asia, Vol. 11, No. 3, July- Sep, Retrieved on 12th Sep, 2013 from 8. ANON.Report of the Study Group on Environment, pp. 9-10; Retrieved on 15th Sep, 2013, from 9. Munyao, J.N.,(2010).Use of Satellite Products to Assess water Harvesting Potential in Remote Areas of Afrrica (M. Tech Theses). Potential+in+Remote+Areas+of+Afrrica&oq=Use+of+Satellite+Products+to+Assess+water+Harve sting+potential+in+remote+areas+of+afrrica&aqs=chrome..69i57.733j0j8&sourceid=chr : Retrieved on 10 th Aug, 2013 from. pp Bengtson, H.Retrieved on 16th Oct,2013 from Classification, Soil.chapter 5; Retreived on 14th Sep from Knox County Tennessee, Stormwater Management Manual, section on the Rational Method; Retrieved from 3%20Rational%20Method.pdf.

33 13. Retrieved on 19th Oct,2013 from Regional Plan, 2021, National Capital Region Planning Board, Chapter 8, Public Health Engineering Department, Rajasthan. : from 8%20Water.pdf, retrieved October 15th, Padmavathy A. S., Raj, K. G., Yoearajan, N., Thangavel, P. & Chandrashekhar, M. G. (1993).Check dam site selection using GIS approach : Adv. Space Res. 13(11), Gupta K.K., Deelstra J.and Sharma K.D.Estimation of water harvesting potential for a semiarid area using GIS and remote sensing. : Remote Sensing and Geographic Information Systems for Design and Operation of Water Resources, 1997.