Effect of Tube Well Drainage on Water Logging and Salinity in Kafur Dheri Unit Peshawar

Research study was conducted at Kafur Dheri Unit, Peshawar during 2002 to find the effect of tube well drainage on water logging, salinity and sodicity. Discharge of 18 tube wells was determined by volumetric method. Water table depth at 11 locations was measured with the help of electric water level indicator. Auger-hole method was used to determine hydraulic conductivity at 8 locations in the research area. Soil and water samples collected from 25 locations were analyzed for electrical conductivity (EC), pH, sodium adsorption ratio (SAR) and residual sodium carbonate (RSC) and were compared with soil and water quality standards adopted by WAPDA. Discharge of tube wells ranged from 7.95 to 54.52 l s-1, with overall average of 32.37 l s-1. Generally, the actual discharges of tube wells were lower (6 to 53%) than their design discharges. Also 53% tube wells were out of order. The water table depth ranged from 0.14 to 0.84 m from the ground surface with an average of 0.41 m. In waterlogged areas mostly water table was very shallow and caused a severe problem for crops, however, water table was deep where natural drains were passing nearby or where tube wells were working properly for a long time. Dominant soil texture in the area was loam and clay loam, and hydraulic conductivity ranged from 1.03 to 3.54 m/day with an average of 1.53 m/day. Results showed that the salinity is not the major problem in the area. Generally, electrical conductivity of the soil and water was in the range of 0.30 to 2.80 and 0.36 to 1.28 dS m-1, respectively. Soil and water of Kafur Dheri Unit are moderately alkaline in nature with pH ranging from 7.59 to 8.26 and 7.45 to 8.83, respectively. SAR of soil and water ranged from 0.10 to 1.02 and 0.13 to 3.15, respectively. There was no residual sodium carbonate in soil and water samples. It is concluded from the study that water logging is still the major problem of the area; hence, rehabilitation of existing drainage system is necessary