RS and GIS application in site selection for artificial recharge of ground water tables in dry regions of Isfahan (central part of Iran)


F. Amiri
Faculty Member of Scientific Board
Azad University Branch Bushehr, Iran
amiri_fazel@yahoo.com
fazel.amiri@gmail.com

M.R.Chaichi
Department of Rangeland Sciences
Science and Research Institute
The Islamic Azad University
Poonak, Tehran, Iran.

A.Nadi
Master of GIS
Department of Natural Resource
Isfahan, Iran.

Abstract
Flood management an important to recharge ground water tables in dry land regions where the agricultural and range lands are vulnerable to soil erosion. Remote sensing and GIS systems are effective and efficient techniques in watershed management and flood distribution over rangeland. In the present research the soil, slope, aspect and land function maps of a research site in south Isfahan province were prepared and water feeding sites were identified using a GIS system. The results indicated that the feeding sites identified were the best sites to feed the water tables in practice.

Introduction
More than 99 percent of the sweet water on the earth have been stored in the under ground water tables. Most of the civilizations in the arid and semi-arid environments have been dependent of under ground water resources because of the climatic conditions (Isfahan Regional Water Organization, 2002; Kiaherati, 1997). Iran is located in arid and semiarid part of the world where the average annual rainfall in 74 percent of the whole country is less than 250 mm per annum. Because of erratic and unstable rain fall distribution in arid environment, the under ground water reserves are the most reliable sources of sweet water in these areas (Arasteh, and Vahhadj, 1997).

One of the most efficient ways to fight the drought crisis in these areas in to recharge the water tables either by natural or artificial methods (Reid and Dreiss, 1990). The natural system, the rain fall in infiltrated in the under ground tables through the streams, rivers or under ground currents (Hendrick, et al., 1991). This volume of water is not enough to support a substantial development of artificial feeding of under ground water table’s methods which tends to feed water to the ground through infilterble layers on the soil surface (Rebhun, et al. 1968, Samani, and Behrooz, 1997). A successful water feeding project is dependent of a good design and maintenance (Berger, 1992 and Samani, et al. 1997).

Materials and Methods

The geographical characteristics of experimental site:
The experimental site is located in Northern-Marbour watershed located in 165 km south of Isfahan. The site is 2750 meters above sea level which experience a long dry period during a year because of its rainfall distribution regime. The short erratic and intensive rainfalls during early season causes flood Problems and water loss during early spring. Northern-Marbour watershed area is 72487 ha which in Semmirom region of Karron branch watershed (Isfahan Regional Water Organization, 2002).

Procedures
To find a suitable site for the water feeding project the following information were gathered
  1. The land use map
  2. Slope map
  3. Soil texture map
  4. Streams map
  5. Climatic information
All this information was obtained from data bonks and library sources as well as frequent field trips. The data were classified and interpreted as follow:
  1. The land use map (layer 1):
    2. The land use map was produced using satellite images TM and was updated by field trips. The following land uses were identified on the map: A. rangelands, B. Agricultural lands, C. Forest lands

    In the land use map, the rangeland site was determined as a suitable site for water feeding project. This map was digitalized using a computer software (Ilwis 3.2) (attached map No,1 and 6).

  2. Slope map (layer 2)
    A topographic map (Scale 1/50000) was prepared and by comparing the Angelo Saxon and square methods it was manipulated manually. Based on the final outcome the slope map of the site was prepared which was directly digitalized by a digitalized table and Ilwis 3.2 computer software. The site was divided into three slope categories of <2%, 2% - 5% and > 5% (map No. 2 attached).

  3. Soil Texture map (layer 3)
    4. To prepare the soil texture map of the site, the whole region soil map and land use maps were used. With frequent field trips the soil texture data was updated. The available Soil textures were classified as loamy, clay, sandy, loamy clay, clay sandy, silty, clay loam, silty clay and loamy silty which among there only loamy clay and sandy clay soil textures were identified as suitable soils for water feeding project. This map was digitalized by the previous procedure (map No.3 attached).

  4. Stream map (layer 4)
    The map was also prepared using the topographic map of the whole region and was updated by field trips. The available streams were classified according to staler criteria by which the streams with adequate Debby to feed the underground water fables were identified and the rest were eliminated (map No.4 attached)

    Climatic information
    This data were used for estimate the rainfall sufficing CY to recharge the underground water tables as well as the return cycle of dominant rain falls. Based on the available information, Sites with 210 mm annual rainfall, considering other factors viz: evapo-transpiration rainfall distribution, maximum, minimum and mean temperature, were chosen for water feeding project.


Results and Discussions
Four information map layers were used to identify the suitable sites for water feeding project. The suitable sites were identified by number 1 and unsuitable ones with 0 on the find map. All the values on the in formation layers were multiplied to one another and the final map with sites which had no zero value even in one formation layer was produced which was used for water feeding project. The first step in this system in to find a suitable watershed (Attarzadeh and Parand, 1995; Micheal and Shif, Arasteh et al.)

The following criteria are used to choose a suitable site for artificial water feeding project.
  1. A available infilterble layers in under ground structure
  2. Under ground layers have enough water storage potential. With good conductivity.
  3. There should be no saline layers with soluble salts to contaminate the stored water.
  4. Water feeding should be applied along the level lines to ensure uniform water spreading over the watershed.
  5. The un-arable low value lands should be used for water feeding projects.
The best sites to apply water feeding projects are coarse texture soils, alluvial sites, stony texture soils, Small River and streams with sandy beds and temporary spring streams. The suitable sites for water spreading project are identified by different methods. In any method all the necessary data should be integrated and analyzed as a whole system.

Geographical Identification System (GIS) could be efficiently used in this regard. There an ability to process, analyze and demonstrate the outcome by histograms graphs, tables and proper maps using this system. These abilities have made GIS a power tool to interpret the data in all the sciences related to geographical sites.

The water feeding project applied Northern-Marbour in 1998 is a good evidence of applicability and accuracy of this system in watershed management.

Suggestions:
  1. In land use and land suitability evaluation, more sub divisions for different agricultural and range lands with different proposes should be identified.
  2. To provide with the slope map we should use the DEM of the site to produce a more accurate map for each pixel rather than for the whole site.
  3. The slopes more than 2% should be investigated their output in higher gradients should be identified. In site identification projects for water feeding, preparation of more information layers such as the distance from river, geology, hydraulic slope vegetation cover both agricultural and range cover, slope aspects etc, are suggested.
The project effects on under ground water tables should be investigated before the project commencement.



Reference:
  1. Arasteh, P. D. and S.R Vahhadj. 1997. Simulation of groundwater flow in an artificial recharge system. Proc. 8th International Conference on Water Resour. Manage., Isfahan, Iran, pp.79-87.
  2. Berger. D. L. 1992. Ground water recharge through active sand dunes in northwestern Nevada. Water Resour. Bull. 28(5): 959-965.
  3. Hendrick, J. M. H., A. S. Khan, M. H. Bannink, D. Brich and C. Kidd. 1991. Numerical analysis of groundwater recharge through stony soils using limited data. J. Hydrol. 127:173-192.
  4. Kiaherati, J.1997. Evaluation of water spreading project of Moughar region on under ground water tables. M.S. project, College of Agriculture, Isfahan University of Technology.
  5. Isfahan Regional Water Organization. 2002. Water artificial recharge of Kahrouyeh River Report.
  6. Rebhun, M. and J. Schwarz. 1968. Clogging and contamination processes in recharge wells. Water Resour. Res. 4(6): 1207-1217.
  7. Reid, M. E. and S. J. Dreiss. 1990. Modeling the effect of unsaturated, stratified sediments on groundwater recharge from intermittent streams. J. Hydrol. 114:149-174.
  8. Samani, N. and S. Behrooz. 1997. Optimal distribution of artificial recharge and its stability. Proc. 8th International Conference on Rainwater Catchment Systems, Tehran, Iran, pp. 182-189.