Investigation of Fresh Water Harvesting from Playa’s Wetlands

Abstract

Playas are low-lands which is considered to be the locations of accumulation of superficial and ground waters fromhigher elevations and these waters have different types of salts and various salinity level. Therefore, because of lack ofrainfall and fresh-water both for human and animal useage or even for plants, it is needed to apply proper methods toharvest fresh water from these saline-waters to develop agricultural and animal husbandry industry in this areas.Therefore, the research will try to investigate fresh water harvesting from playa’s saline waters with the aid of saloarenegy and without implementation of import and complicated technology. The method is called Evaporating WaterHarvesting (EWH). In this method, to install plastic covers on playa’s wetlands, productive fresh water obtained bycondensation of evaporated water from soil surface (disturbed and undisturbed suface) was measured. Factors such as soilgenesis, soil’s salts, water table, rate of saolar radiations and atmosphere temperature changes, had influence on the rateand term of water harvesting. The result showed that Daily average of gathered water from 1m2 soil surface in disturbedstatement was 0.3 liter. The Minimum and maximum rates were 0.1 and 0.35 liter in May and July, respectively and Dailyaverage of gathered water from 1m2 soil surface in undisturbed statement was 0.03 liter. The Minimum and maximumrates were 0.0 and 0.05 liter in May and July respectively. Then SPSS 11 software for being any relationship betweensites’s water harvesting and environmental factors (such as water table, temperature, relative humidity, sun shine hours)was used. Results showed that the mean correlation of 99 percent had been between rate of sites’s water harvesting andtemperature and water table factors and 95 percent to sun shine hours. At last, water table map was drawn. This methodhas some advantages such as producing fresh waters in playas, simplicity and being conomical and so on (see resultsection), and some disadvantages including limitation by using plastic covers, calcic and gypsic horizons in soil, not beingusable in higher water tables (>3m).