A mathematical model is developed for the estimation of groundwater recharge through surface drains for both free flow as well as detained flow conditions. The Dupuit-Forchheimmer equation is solved using the Crank-Nicolson central finite difference scheme, to obtain the mound height matrix. The Gaussian elimination method was used to solve the matrix, to obtain the mound height at different radial distances across the drain. Various hydrogeological parameters like hydraulic conductivity, specific yield, etc. are determined by field investigations. Surface runoff available due to a particular rainfall event is correlated with recharge rate available in the drain. The model gives volume of water recharged for various rainfall events under different antecedent moisture conditions for both free flow and detained flow conditions. The value of recharge rate computed by using the model for a particular depth of flow in the drain is matched with the observed values. The model is more sensitive to change in the value of specific yield than hydraulic conductivity.

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The present study was conducted to determine the diversity of weed species in wheat fields of the district Rajouri (J&K). For analyzing diversity 20 quadrats of (1m.×1m.) were randomly laid down in each block. In every set of quadrat frequency, density and abundance was observed throughout the cropping season and IVI (Important value index) was determined. During the course of field study it was reported that the maximum infestation was shown by grassy weed Avena fatua having maximum density (10.15, 12.12, 7.30, 9.35, 10.6, 8.55 from site 1-6 respectively) and IVI (35.71, 43.49, 30.27, 33.91, 32.59, 32.11 from site 1-6 respectively) in all the selected sites. While the least dominant weeds were Calotropis procera, Conyza japonica, Cannabis sativa, Rumex acetosa, Euphorbia prolifera and Sonchus asper etc. A total of 116 weed species belonging to 3 monocot and 27dicot families were reported from the target site.