| GISdevelopment.net ---> Application ---> Natural Resource Management |
Remote Sensing and GIS Approach for Delineating and characterization of Groundwater Potential Zones in Hard Rock Terrain
D.M.D.O.K.Dissanayake
Department of Earth Resources Engineering,
University of Moratuwa, Sri Lanka
Abstract
For a long time, India had been dependent on monsoons to meet its fresh water requirements. However, over the years groundwater is being increasingly used for this purpose. This has resulted in reducing country's dependency on monsoon, but at the same time has led to depletion of groundwater level. In several areas of the country, such as Delhi, parts of Uttar and Uttaranchal Pradesh, Karnataka, Maharashtra and Tamil Nadu, groundwater levels are perilously low. Therefore, there is an urgent need to address the issue of management of water resources in these areas in a sustainable manner.
Integrated Remote Sensing and GIS can provide an appropriate platform for converging diverse data sets for analysis geared towards decision making in groundwater management. In this study, an integrated Remote Sensing and GIS based methodology was developed and tested for delineating and characterization of groundwater potential in hard rock terrain spreading over 2684km2 in the districts of Sirmur, Solan and Shimla of Himachal Pradesh.
In generation of hydrogeomorphological map, Index Overlay Method was used. This simple and straightforward method enables to combine multilayer thematic maps. The accuracy of this method is totally dependant on human judgment. Area covering highly dissected structural hills (3.2%) indicated very poor groundwater potential; moderate(33.92%) to lower dissected hills(52.24%) areas indicated moderate to low groundwater potential of total area while very high groundwater potential was indicated in river terraces, lower piedmont zones, sand bars, point bars, highly fractured areas, braided river and alluvial planes.
Water quality analysis indicated that most of the water quality parameters were within the permissible limit for human consumption. However, iron content was very high in few places and this may be due to reasons such as rusted iron casing of tube wells, and, or, contamination of groundwater with the presence of iron rich rock and soil. Hardness is comparatively high since this area is rich with limestone.
1. INTRODUCTION
Remote Sensing and GIS are playing a rapidly increasing role in the field of hydrology and water resources development. Remote Sensing provides multi-spectral, multi-temporal and multi-sensor data of the earth’s surface. One of the greatest advantages of using remote sensing data for hydrological investigations and monitoring is its ability to generate information in spatial and temporal domain, which is much crucial for successful analysis, prediction and validation (Saraf,1999).
However, the use of remote sensing technology involves large amount of spatial data management and requires an efficient system to handle such data. This is compensated by GIS technology which provides suitable alternatives for efficient management of large and complex databases.
Information from satellites is becoming more and more important in our life, including for research related to environment, urban planning, military strategy, navigation, etc. When we consider the environmental research, an important part of satellite information has relevance to water; being an element most essential for man, its phases and peculiarities, both spatially and temporally.
Water resources in India are unevenly distributed, both spatially and temporally. Idiosyncrasies of monsoon and diverse physiographic and geomorphological conditions give rise to unequal distribution of water. Over the years, increasing population, urbanization and expansion in agriculture has accentuated the situation. As a result of unplanned and using inappropriate and unscientific methods of exploitation of groundwater eventually leads to water stress conditions. Even now, some parts of the country are facing acute water crisis. Despite being a very important part of the nation’s growth, analysis of water resources has been fragmentary. Thus, as a part of filling the gap, this study focuses on development of remote sensing and GIS based analysis and methodology for groundwater prospecting in hard rock terrain.
In order to demonstrate the integrated remote sensing and GIS based methodology, an area which forms the Giri catchment, spreading over 2684km2 in the Districts of Sirmur, Solan and Shimla of the State of Himachal Pradesh was selected. The main objective of the study was to delineate groundwater potential zones and suitable sites for human consumption in the Giri catchment.
2. STUDY AREA
The study area lies between 300 25’ to 310 16’N latitude and 770 02’ to 770 44’E longitude and is spread over about 2632km2 in the Districts of Sirmur, Solan and Shimla in the State of Himachal Pradesh, India. Its boundaries are the catchments of Sutlej river in the north-west, Tons and Yamuna in the north-east and Ghaggar in the south-west.
3. PHYSIOGRPHY
Figure 1
A greater part of the Giri catchment lies in the middle Himalaya and Siwaliks and is hilly with deep and narrow valleys separated by spurs and ridges.
The Giri River originates at the altitude of 3,358m at Kupar Tibba on Kupar Dhar dividing Giri and Ton River watersheds in Shimla district and it meets the Yamuna river at the altitude of 438m at Rampur Ghat.
Sixty four percent of the Giri catchment area falls under high altitude hills from 1500m to 3000m. The area under mid altitude hills ranges from 1000m - 1500m and low altitude hills less than 1000m are 30 and 5 percent respectively. Almost the whole catchment contains steep to very steep slopes.
4. CLIMATE
Climate, varying with altitude, is sub-humid and subtropical in lower part of the track lying in the Siwaliks to wet temperate in the upper part in central Himalaya. The precipitation of the catchment varied from 824 mm at Kotkhai to 1,933 mm at Sarahan The mean precipitation of the catchment is 1,287mm (TABLE 1). A bulk of the precipitation occurs in monsoon season from June to September. Winter rains occur from December to March. The snow fall is a normal feature in areas above 1,800m. The droughts occur both in pre and post monsoon periods with March, April, May, October and November being generally dry months. The region has distinct seasons of summer (April-June), monsoon (July-September), autumn (October-November) and winter (December-March). Summers are hot in the Siwaliks with temperature rising to about 420C, while winters are cool.
TABLE 1 - Precipitation data around the Giri Cathment (in mm)
| Station | Jan. | Feb. | Mar. | Apr. | May. | Jun. | Jul. | Aug. | Sep. | Oct. | Nov. | Dec. | Annual Av. |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Shallaroo | 161.2 | 39.6 | 52.5 | 72.4 | 70.3 | 255.8 | 226.1 | 245.4 | 81.1 | 29.9 | 27.2 | 13.1 | 1274.4 |
| Theog | 49.3 | 67.7 | 82.3 | 53.2 | 92.6 | 123.4 | 181.1 | 147.1 | 107.2 | 21 | 9.3 | 29.1 | 964.8 |
| Kasumpati | 62.2 | 50.7 | 45.4 | 34.1 | 79.3 | 207 | 248.9 | 265.5 | 105.7 | 35.8 | 16 | 15 | 1185.6 |
| Shimla | 60 | 66 | 65 | 55 | 70 | 120 | 415 | 430 | 290 | 50 | 25 | 55 | 1701 |
| Kotkhai | 46.9 | 66.9 | 53.9 | 42.8 | 81.9 | 95.6 | 138.1 | 166.9 | 85.5 | 18.9 | 10.4 | 19.1 | 823.9 |
| Junga | 78.6 | 55 | 56.6 | 31.9 | 91.6 | 191.1 | 232.1 | 272.7 | 77.9 | 42.9 | 35.2 | 32.1 | 1197.7 |
| Solan | 81.6 | 78.1 | 79 | 42.1 | 68.1 | 138.9 | 253.8 | 215.1 | 84.7 | 35.4 | 19.4 | 29.4 | 1118.7 |
| Nauni | 47.2 | 55 | 62.9 | 31.8 | 69 | 160.4 | 249.2 | 228.1 | 117.4 | 51.7 | 28.6 | 61.2 | 1162.6 |
| Ochhghat | 80 | 90 | 115 | 30 | 35 | 150 | 290 | 260 | 145 | 17 | 29 | 40 | 1280 |
| Chall | 75 | 60 | 70 | 135 | 45 | 135 | 385 | 355 | 180 | 12 | 25 | 30 | 1482 |
| Kandaghat | 67 | 72.6 | 64 | 36.3 | 69.3 | 167.1 | 252.6 | 252.6 | 105.4 | 20.8 | 13.1 | 52.7 | 1176.5 |
| Kasaull | 57.4 | 70.5 | 66.5 | 48.3 | 71.8 | 88.9 | 471 | 545.8 | 223.8 | 23.7 | 10.8 | 45.7 | 1824.8 |
| Saharan | 122.2 | 118.7 | 98.2 | 84.7 | 87.4 | 175.4 | 357 | 300.8 | 207.7 | 118.1 | 111.5 | 152.2 | 1933.4 |
| Pachhad | 55.5 | 73.9 | 61.2 | 38.1 | 62.2 | 117.5 | 325 | 255.8 | 118.7 | 31.2 | 17.3 | 51.9 | 1208.4 |
| Nahan | 47.3 | 57.9 | 44 | 31.4 | 40.4 | 187.7 | 510.6 | 663.1 | 157.1 | 46.8 | 29.9 | 67.6 | 1738.8 |
| Rajgarh | 73.5 | 73 | 84.4 | 49.6 | 68.5 | 144.1 | 306.5 | 228.7 | 131 | 31 | 41.7 | 60.9 | 1292.8 |
| Poanta | 32.9 | 26.2 | 15.1 | 13.6 | 58.6 | 185.1 | 406.2 | 609.7 | 210.9 | 24.8 | 3.1 | 25.2 | 1511.5 |
| Renuka | 41.2 | 47.7 | 43.3 | 37.7 | 33.8 | 129 | 309.5 | 276.6 | 80 | 22.5 | 8.2 | 53 | 1083.2 |
| Rohru | 81.6 | 86.1 | 121 | 52.4 | 40.9 | 58.9 | 153.4 | 157.1 | 85.5 | 27.9 | 23.5 | 52.7 | 941.3 |
| Jubbal | 75.4 | 81.5 | 135.1 | 61.9 | 84.3 | 83.3 | 231.3 | 170.1 | 99.5 | 31.5 | 14.1 | 43.5 | 1112.5 |
| Chopal | 110.2 | 73.1 | 115.2 | 50.1 | 69.7 | 82.6 | 222.4 | 203.9 | 104.4 | 32.5 | 24.1 | 38.8 | 1124.1 |
5. DATA USED
IRS LISS III and PAN images, LANDAST 7 ETM and PAN images, STRM DEM data, Survey of India Arial photographs and Topo sheets, Rupke Geology Map and Rain fall data provided by Regional Research Station of Himachal Pradash Agricultural University, Dheulakunan were used to generate various thematic maps for this study.
6. METHODOLOGY
The study was carried out in several stages. Lithological boundaries, structure and geomorphic features were delineated from aerial photographs on the scale of 1:25,000 by stereoscopic analysis. Arial photographs and enhanced satellite data were interpreted by visual interpretation. Based on differences in dissection patterns and tonal variations, the lithological boundaries, as well as major geomorphic features were demarcated. Thereafter, thematic layers for geology, geomorphology, lineament and structure, drainage, slope, aspect etc. were generated.
Occurrence of groundwater is related to subsurface conditions which requires very complex analysis; subsurface features are dependent on geology and landforms in the area Therefore, it is necessary to integrate different surface as well as subsurface features in order to acquire comprehensive knowledge on groundwater prospects of an area. In order to demarcate the groundwater potential zones the above thematic layers were integrated in the GIS environment. The different ranking and weightages were given for each thematic layer and their parameter respectively (TABLE 2).
The Index Overlay Method is one of the best methods of intergrating geological data to generate final hydrogeomorphological map and demarcate the potential zones for groundwater prospecting. Firstly, primary water prospecting map (1:50,000) was generated. This was followed by two weeks of field investigations along selected traverses for verification purposes and water quality analysis. Final hydrogeomorphological map was generated according to ground truth data and identified suitable sites of groundwater extraction for human consumption.
TABLE 2 - Theme Ranking for Index Overlay Method
| Theme | Geology | Geomor-phology | Slope | Aspect | Drainage Density | Rain Fall | Structure |
|---|---|---|---|---|---|---|---|
| Rank | 8 | 9 | 9 | 6 | 7 | 6 | 7 |
| Weight | 1-10 | 1-10 | 1-10 | 1-10 | 1-10 | 1-10 | 1-10 |
7. THEMATIC LAYERS
8. RESULTS
Figure 9 - Final Hydrogeomorphological Map
TABLE 3 - Groundwater potential
| Groundwater Potential | Area % |
|---|---|
| Very Low | 3.20 |
| Low | 52.24 |
| Moderate | 33.12 |
| High | 7.00 |
| Very high | 3.60 |
9. CONCLUSION
This study shows the importance of Remote Sensing technique, which is an information tool and provides synoptic coverage sufficiently accurate and comprehensive spectral, spatial and temporal information of the earth surface. Further, this study confirmed that the effectiveness of GIS as a system that provides ample opportunity to efficiently store and manipulate Remote Sensing data and other spatial and non spatial data.
In generation of hydrogeomorphological map, Index Overlay Method was used. This simple and straightforward method enabled for combining multilayer thematic maps. The accuracy of this method is totally dependant on human judgment. Determination of weightage of each class is the most crucial aspect in integrated analysis, as the output is mostly dependent on the assigning of appropriate weightage. Primary porosities are almost nil in hard rocks and therefore lineaments are very much important for groundwater occurrence and recharging; therefore, high rank and high weightages were given for lineament. In this study, a single weightage of 7 was given for all the lineaments including faults and folds. Permeability and porosity controls the groundwater occurrence and recharging of the area and porosity and permeability directly depend on the lithology of the area; accordingly, geology was ranked 8 and different weightages were given for different formations. Highest weightage was given to unconsolidated rock types of the study area. Slope is also a crucial parameter for occurrence and recharging conditions of groundwater in a particular area; runoff will be more and infiltration is less in steep slope areas; therefore, slopes were ranked 9 and different weightages were given for different slope classes. Drainage density is also an important parameter for groundwater occurrences and recharging; in hard rock terrains, high drainage density and low infiltration were observed; therefore, drainage density was ranked 7 and different weightages were given for different drainage densities. Annual rainfall is another crucial parameter for groundwater occurrence and thus ranked 6; different weightages were given for different rainfall classes.
In final hydrogeomorphological map, area covering highly dissected structural hills (3.2%) indicated very poor groundwater potential. Moderate(33.92%) to lower(52.24%)dissected hilly areas indicated moderate to low groundwater potential. Very high groundwater potential was indicated in river terraces, lower piedmont zones, sand bars, point bars, highly fractured areas, braided river and alluvial planes.
Low recharging rate, generally high runoff mostly due to hard rock terrain and excessive withdrawal of groundwater for irrigation which has led to continuous depletion of groundwater table over the years would have resulted in depletion of groundwater in many places. Detailed lithological studies have to be conducted to confirm the actual causes.
Water quality analysis indicated that most of the water quality parameters were within the permissible limit for human consumption. However, iron content was very high in few places and this may be due to reasons such as rusted iron casing of tube wells, and, or, contamination of groundwater with the presence of iron rich rock and soil. Again, to confirm the real cause(s) for the presence of high iron content, a detailed lithological study has to be conducted. Hardness is comparatively high since this area is rich in limestone.
Rainwater harvesting or any other artificial recharging method is more suitable for improve the groundwater potential in low potential areas. Artificial recharging is the process of augmenting the natural movement of surface water into underground formations by artificial methods. This is accomplished by constructing infiltration facilities or by inducing recharge from surface water bodies. In hard rock areas, the underlying lithological units do not have sufficient porosity and permeability. In these areas, groundwater recharge falls short of the water that is being taken out of the aquifers. Thus, additional recharge by artificial methods becomes a sheer necessity to meet the water deficit.
Recharging process can be made effective and efficient to meet the demands for water for human consumption through planning and using appropriate scientific methodology and tools. In this context, integrated Remote Sensing and GIS can be used as a powerful and an effective tool for planning for artificial recharging structures. However, this tool is yet to be used widely for planning and designing for artificial water recharging in India.
10. REFERENCES
- Choudhury, P. R. and Saraf A.K, 1997, Integrated Application of Remote Sensing and GIS Groundwater exploration in hard rock terrain, Proceedings. Int. Symp. on Emerging trends in Hydrology, Department of Hydrology, Roorkee, September 25-27, 1997, Vol. I, 435-442.
- Choudhury, P. R. 1999, integrated remote sensing and GIS techniques for groundwater studies in part of Betwa Basin, Ph.D. Thesis, Department of Earth Sciences, University of Roorkee, India.
- Dissanayake, D.M.D.O.K, Remote Sensing and GIS approach for delineating groundwater potential and quality suitability - Giri Valley catchment, Thesis on PG Diploma in RS and GIS - 2005
- Saraf, A.K. and Jain, S.K., 1996, Integrated use of remote sensing and GIS methods for groundwater exploration in parts of Lalitpur District, U.P., International conference on Hydrology and Water Resources, New Delhi, Dec 20-22, 1993, 251-259.
- Saraf, A. K. and Choudhury, P. R., 1998, Integrated Remote Sensing and GIS for Groundwater Exploration and Identification of artificial recharge sites, International Journal of Remote Sensing. 19(10), 1825-1841.
- Saraf, A. K. 1999, A report on Landuse Modelling in GIS for Bankura District, Project sponsored by DST, NRDMS division, Govt. of India