Applying nature-based solution at Nagdaha
Like many urban and suburban lakes in Nepal, Nagdaha is facing problems that comes with rapid urbanization including catchment land-use change, pollution, sediment run-off, and lake resources overexploitation. With a focus on biodiversity and water quality, we are currently working on a sediment and nutrient retention pond. Our main objective is to reduce the effects of pollutants, sedimentation, and nutrients runoff on the lake originating from the activities at the stone spout and agricultural land-use in the catchment.
Our initial observation identified the south-west part of the lake’s catchment to be the problematic region. It is used for agriculture (mainly rice) and for housing which is under construction by one of the largest corporations in the country, Chaudhary Group or CG. The inlet is also located in this sub-catchment where approx. 70% of the water comes from the stone spout (spring) located about 200m west of the lake in the agriculture area (Figure 1). At the stone spout, people use the water directly at the site mainly for bathing, washing clothes, and irrigation and all the used water then drains into the inlet. As this area of the south-west catchment (sub-catchment A) is predominately an agricultural land and also locates a stone spout which is being used for domestic purposes, we hypothesized that the run-off and inlet water from this area would have high nutrient content while the construction area (sub-catchment B) would be mainly responsible for the sedimentation loading.
