Depth to Gravel Layer Mapping to determine Potential Areas of Artificial Groundwater Recharge in Patan Area
Date
2012
Authors
Maharjan, Ganga Ram
Journal Title
Journal ISSN
Volume Title
Publisher
Department of Geology
Abstract
Groundwater has been extensively used in Kathmandu Valley through dug wells, ponds and
dhunge dharas (stone spouts) since ancient period. Shallow groundwater was tapped through dug
wells and dhunge dharas. Rapid urbanization and increasing demand have however put enormous
stress on the traditional water supply system especially as current municipal water supply barely
fulfills 25% of the demand. Even in those days, recharge ponds were made and water was brought
from the valley rims through long canals to recharge the system.
Local geology and the geomorphologic factors influencing the infiltration and recharge rates.
Points located on terraces have relatively higher infiltration rates than those located on low lands
due to high water level in lowlands which rejects rainwater recharge. The areas around
Jawalakhel, Gabahal, Kumaripati and Lagankhel in Patan show immense potential for rainwater
recharge. As dug wells and shallow tube wells have higher recharge rates than the pits and
infiltrometers due to their access directly to the aquifer horizons, dug wells would be good
structures for recharging shallow groundwater even in places lies in Kalimati Formation. More
than 50% of the study area is high recharge potential area which mostly covers in the Southern
and Western part of the study area according to the geology, topography and infiltration rate of
the region. The percentage of coarse material is about 90% at Lagankhel area especially Patan
Hospital periphery and infiltration rate is 1.2 cm/min which is relatively higher than other study
area. It is concluded that Lagankhel area is more feasible than others.
Description
Keywords
Gravel layer, Potential areas, Artificial groundwater