Civil Engineering Department, BRCM College of Engineering and Technology, Bahal, Haryana, 127028, India.
Agricultural and Food Engineering Department, India Institute of Technology, Kharagpur, India.
Environ Monit Assess. 2019 Jul 29;191(8):522. doi: 10.1007/s10661-019-7674-y.
Non-point source (NPS) pollution has been emerged as a major cause for reduced water quality of a lake due to increased human interference and disturbances in the natural condition of the surrounding catchment. The impact is, even more, worsening in the monsoon season when there is increased surface runoff. In the present study, an attempt has been made to predict the seasonal (monsoon) NPS loading in terms of sediment, nitrogen, and phosphorous in Maithon reservoir using Soil and Water Assessment Tool (SWAT) hydrologic model. The SWAT model was initially calibrated using monthly runoff and sediment yield data of monsoon period for the year 1998-2005 using observed data of Rajdhanwar station followed by its validation for the observed monthly runoff and sediment data from Giridih and Santrabad for the same duration. The calibrated SWAT model was used to predict the sediment, total nitrogen, and phosphorous influx in the Maithon reservoir. It has been observed that average sediment yield from different micro-watersheds varies from 0.231 to 7.458 ton/ha, while average monthly nitrogen and phosphorous yields vary from 0.224 to 1.377 kg/ha and 0.073 to 0.363 kg/ha, respectively, during the monsoon period. On the other hand, the net monthly average sediment yield and total nitrogen and phosphorous yields in the reservoir were found to be 1.53 M ton, 1834.2 kg, 191.1 kg, respectively. The results indicate there is a substantial influx of nutrients and sediments into the Maithon reservoir. The study not only provides insights on the potential NPS pollutant loading in the reservoir but also enables to identify the hotspot of NPS pollution where immediate mitigation measures have to be taken at priority basis.
非点源（NPS）污染已成为湖泊水质下降的主要原因，这是由于人类对周边集水区的干扰和自然条件的破坏。在季风季节，由于地表径流量增加，这种影响更加恶化。本研究尝试使用土壤和水评估工具（SWAT）水文模型来预测迈通水库季节性（季风）NPS 负荷的情况，包括泥沙、氮和磷。SWAT 模型最初使用 Rajdhanwar 站的观测数据对 1998-2005 年季风期的月径流量和泥沙产量数据进行了校准，然后使用 Giridih 和 Santrabad 的观测月径流量和泥沙数据对其进行了验证。使用校准后的 SWAT 模型来预测迈通水库的泥沙、总氮和磷的输入量。结果表明，不同小流域的平均泥沙产量从 0.231 到 7.458 吨/公顷不等，而平均每月氮和磷的产量分别从 0.224 到 1.377 千克/公顷和 0.073 到 0.363 千克/公顷不等，均发生在季风期。另一方面，水库的月平均净泥沙产量和总氮、总磷的产量分别为 1.53 百万吨、1834.2 千克和 191.1 千克。结果表明，大量的营养物质和泥沙流入了迈通水库。该研究不仅提供了水库中潜在 NPS 污染物负荷的信息，还能识别 NPS 污染的热点地区，以便优先采取立即缓解措施。
