|
Page 1 of 1 Identification of artificial recharge sites along the Sutluj riverine Hina Ibrar and M. Ather Javaid Department of Space Science, University of the Punjab, Lahore. Email: hina.ibrar@gmail.com INTRODUCTION Water reservoirs always play a vital role in the development and economics of a country, especially, countries like Pakistan who are having agriculture as its back-bone. Artificial recharge can enhance the agricultural development by increasing the water storage. From space earth looks blue. It contains an amazing water wealth of 1360 million km3, if spread on earth, it would cover a height of 2.7 km. The distribution of wealth is 97% in sea, 2% in glaciers and ice-caps and 1% groundwater, too far to exploit out of this total amount, 05 million km3 is evaporated by the solar pressure system (86% from sea & 14% from the Earth’s surface). Equal amount falls back out but its distribution is different as the continents evaporation (Rashid, 2002). Due to this many countries are facing water deficiency. The situation is not different in Pakistan. World watch institute, in its report of 2002, stated that two-thirds of the total population would fall in water stress (1000 m3 per person per year). In the 1950, the amount of water available was 5650 m3 per person per year and now up to year 2001 we have about 1200 m3 per person and in 2012, Pakistan will be among the water scarce countries. At the time of independence, Pakistan had total river water of 173 MAF and it lost 33 MAF to India due to “Indus Water Treaty” by giving three rivers (Ravi, Sutluj and Bias). We got Terbela & Mangala with a storage capacity of 14.6 MAF and still the net loss was 18.4 MAF. These dams will complete their lives in next few years. After Indus Water Treaty, Pakistan had only 140 MAF flowing into its rivers out of which total water available for crop use is only 69 MAF including the underground water pumped by private & public tube wells (44 MAF). We are wasting 79 MAF in canals, distributaries, farm water channels and even in fields. In the last few years, pumping of underground water is increasing rapidly and it was 51 MAF in 1998-99 and if we consider the current year, it is almost equal to the amount of water available for recharge (MAF) and might have surpassed this figure. Due to this over exploitation, ground water levels are decreasing in 26 canals out of 43 canal commands (Rashid, 2002). If we look at annual rainfall in the country, it has been decreasing continuously by 40-150 percent since 1994, as recorded at all meteorological stations (Rashid, 2002). IUCN (2005) has given the highest priority to advocate artificial recharge practices and achieving efficiency in water use through adopting integrated approach to manage water and implemented artificial recharge project in Balozai, District Pishin. The present study has been conducted during the year 2007 to identify the artificial recharge sites using GIS techniques in the area which is a rich agricultural land and riverine also. The availability of drinking water is not a problem there. The major problem is that River Sutluj is flowing in depression since a decade. This is depriving the rich agricultural belt of Province Punjab from its major right of water. There are many climatic causes of this depressed situation. Streams get their water from the main river and irrigate the other command areas. But there are no any structures for the people living along the riverside. In flood days they are the most victims. As the study area is possessing 90% of its livelihood in the form of agriculture, the people living along the riverside are using direct pumpage from the river. This pumpage is beneficial during the days of monsoon (or when the river has plenty of water), but, in depressed days these pumping structures are filled by the sediments. As a result the farmer living along the river bank has to face problem. MATERIALS AND METHODS The methodology adopted is based on the overlay analysis of thematic layers. Four thematic layers are used:-
Location of study area The study area is Sutluj Riverine area from the place of Sulemanki Headworks (30°28’.70”N latitude and 73° 51’2.11”E longitude) to Islam Headworks (29°54’15.86 N latitude and 72°32’56.04 E longitude). In accordance to the Irrigation and Power Department (1992), the area is flat with an average slope of 72.29 cm/Km in the south west direction. The most of the area lies as “Abandoned Flood Planes”. Agricultural usage The major crops are cotton, wheat and corn. About 80% economics of the area is developing on agriculture. It is said that Vihari is the town which is yielding cotton equal to the whole province Sindh. The agricultural usage of the study area has been studied with the help of Landsat 149-39 classified image. Climatic Situations The area is hot and dry. The summer season starts from April and continues until October. May, June, and July are the hottest months. The mean maximum and minimum temperatures for these months are about 470C and 28 0C. Dry, hot, and dusty winds are common during summer. The winter season lasts from November to March. December, January and February are the coldest months. The mean maximum and minimum temperatures for this period are about 22°C and 4 °C. Fog is very common during winter. In most of the areas rain falls during the monsoon season from July to September. During winter season there is very little rain, however, deluges and floods can occur (Wikipedia, 2007).  The annual rainfall in the study area is shown in Figure 1. The annual flooding situations of the study area according to “Pakistan Flood monitoring Department” are given in Table1. Table 1 and Figure 2(a & b) show the annual discharge behaviour of the river Sutluj at the points of Sulemanki and Islam headworks, respectively.    Soil situations Whole of the reach from Sulemanki Headwoks to Islam Headworks possesses loamy soil as shown in Figure 3. Which is a good textured soil for both agriculture and water absorption. The infiltration rate of loam is much better than other soil categories. This is the reason that whole of the reach is an agricultural area.  Stream Network The stream network has been created by the help of a geographically gridded map obtained from SCARP monitoring organisation (SMO). Table 2 shows the major canals of the study area while Figure 4 shows the digitised stream network of the study area.   Hydrological Analysis Hydrological analysis is made using GIS. First of all, a DEM is generated using Shuttle RADAR topographic Mission (SRTM) point elevation data. Inverse Distance Weightge (IDW) has been used for the interpolation of pint data to get raster. Next, using the hydrology tools flow direction, flow accumulation, basin and sink were calculated.The hydrological analysis provided the efficiency pillar to the overlay analysis.Figure 5 (a, b,c & d) shows the scatterplots of the calculated hydrogeological parameters.     Overlay Analysis Overlay analysis is the last step.The cause to perform overlay analysis is to locate the sites with good soil, good flow accumulation.The generated thematic data layers of soil, stream, elevation countours, flow accumulation are overlayed using overlay tools. Figure 6 gives the view of identifid artificial rechrge sites.  RESULTS AND DISCUSSIONS After overlay analysis two good artificial rechage sites were identified. Results were extracted in the following two ways:- Location of artificial rechrge sites Site 1 is located at 29035’32.65” N and 7207’52.48” E whie the Site 2 is located at 29059’39.90” N and 72050’52.49” E along the river bank. Factors affecting the identified artificial recharge sites Following are factors which should be considered properly to check the efficiency level of identified sites. (a) River Discharge Efficiency The study area is having the poor discharge.The annual river dischrge ratio needed is 1,20,000 to 1,75,000 but presently peak discharge is approaching 50,000 to 80,000, which is the situation of low flooding. It shows that river will be flooded after a very long time or it will be flashly flooded.The two identified sites shown in Figure 6 will receive a very low amount of water from the river other than flooing days. (b) Precipitation Efficiency The required amount of annual rain fall in the study area is 405 to 428 mm but presently it is 140 to 160 mm as shown in Table 2.The study area is in semi-arid zone and losing its natural recharge through precipitation. It also shows that identified sites will receive a low amount of water from rain. Some artificial recharge techniques based on water shed transfers will be needed to increase the effeciency of the recommended sites. CONCLUSIONS No doubt that source water is necessary and major source is a sufficient precipitation.But, on contrary artificial recharge is needed where water table is low and surface water is scarce.So different artificial recharge structures can be introduced by keeping in view the climatic and hydrogeological aspects of a place. With present conditions, the study area is approaching drought.The way to make the identified artificial recharge sites beneficial is to introduce “Inter WaterShed Transfer” and “Induced Recharge” to these sites.This will help the sites to work properly during shortage of source water. While in days of good discharge peaks in river or healthy precipitation, the water will acuumulate there automatically.
Page 1 of 1
|