PERFORMANCE EVALUATION OF SYNTHETIC ENVELOPES IN INDIRA GANDHI COMMAND AREA, RAJASTHAN

ABSTRACT The present study was undertaken to evaluate the performance of synthetic envelopes for sub-surface drainage under the field conditions at Lunkarnsar Farm, Indira Gandhi Canal Command Area, Bikaner and laboratory conditions at College of Technology and Engineering, Udaipur. Three types of synthetic envelopes viz. HG 22, SAPP 240 and CAN 2 were evaluated by using sand tank model and permeability apparatus to compare their performances in terms of entrance resistance and hydraulic conductivities of soil envelope system. The experiments revealed that the values of entrance resistance for envelope HG 22, SAPP 240 and CAN 2 were 1.95 day/m, 1.33 day/m and 1.51 day/m, respectively of Lunkarnsar soil. The hydraulic conductivities for envelope HG 22, SAPP 240 and CAN 2 of the total thickness (k-total) were found to be 4.53 cm/hr, 5.22 cm/hr and 4.91 cm/hr and of the contact layer (k-contact) were found to be 3.009 cm/hr, 3.62 cm/hr and 3.27 cm/hr, respectively. The hydraulic conductivity of contact layer was found lower than that of the total layer which confirmed the soil envelope interface. The Hydraulic conductivity for SAPP 240 filter was found to be the highest and entrance resistance was found to be lowest. The SAPP 240 filter is recommended for Indira Gandhi Command Area for subsurface drainage system.