0016-7622/2020-95-4-385/$ 1.00 © GEOL. SOC. INDIA | DOI: 10.1007/s12594-020-1447-7 JOURNAL GEOLOGICAL SOCIETY OF INDIA Vol.95, April 2020, pp.385-392 Runoff Induced Soil Erosion and its Impact on the Quality of Water for Upper-Patiala-Ki-Rao Catchment Lying on Shivalik Hills Sushma Walia*, Sarbjit Singh and Richa Babbar Department of Civil Engineering, Thapar University, Patiala – 147 004, India E-mail: sushmawalia@yahoo.com*; sarbjit@thapar.edu; richa.babbar@thapar.edu ABSTRACT In this research paper runoff induced soil erosion and its impact on the quality of water of upper Patiala-Ki-Rao catchment located on Shivalik hills of Punjab and Haryana states of India were quantified. The selected ungauged basin is divided into two sub- watersheds and there are four gauged micro-watersheds nested within it. The simultaneous calibration is carried out for selected ungauged watershed, sub-watersheds and four gauged micro- watersheds to simulate the discharge and soil loss using Arc-SWAT and remote sensing. The model is first validated for four gauged micro-watersheds and then the predicted discharge and soil loss was validated for selected ungauged watershed and two sub- watersheds using a regionalization approach to make sure that the model was representing the watershed as a whole. The results of statistical analysis after thorough manual calibration and validation predicts that the SWAT model can satisfactorily simulate stream-flow and sediment yield for the upper Patiala-Ki-Rao watershed. In addition, water samples were collected for each runoff producing rain event during monsoon season for two years to access the impact of soil loss on the quality of water. INTRODUCTION Runoff induced soil erosion, and its subsequent disposal into the river network via watershed outlets is a serious and continuous global environmental problem impacting soil and water quality (Rawat and Singh, 2017; Edon and Singh, 2019). Runoff induced soil erosion is the process in which surface soil is entrained from one place and accumulates to another new location with the impact of rainfall and runoff (Rawat and Singh, 2017; Rawat and Singh, 2018a; Edon and Singh, 2019). The soil erosion and its transportation process cause damage in many ways which include degradation of surface soil quality, regime problem in stream channels, decreasing the capacity of stream channels, lakes, and reservoirs by deposition of sediments and increasing the cost for maintaining water conveyance structures (Rawat and Singh, 2017; Pradhan et al. 2018). Shiwalik hills situated at the north-western foothills of the Himalayas located in the states of Jammu and Kashmir, Punjab, Himachal Pradesh, Haryana, Uttar Pradesh, Uttarakhand, and union territory of Chandigarh are geologically fragile and highly susceptible to erosion (Singh et al. 2010a,b; Singh et al. 2010; Singh et al. 2012). Whereas Shivalik hills of Punjab are situated along the eastern boundary and share the border of Himachal Pradesh, Haryana, and Chandigarh. This sub-mountainous or semi-hilly area on the foothills of Shivalik is locally recognized as Kandi area, comprises several small watersheds, covered with sandstone, shingle, and fluvial deposits. High intensity and short period rains in the area are common. A big amount (35-45 percent) of monsoon rainfall runs downstream in the torrents causing severe soil erosion. Therefore a plan on soil conservation in the region is needed for decision making and management on the basis of physical properties and scientific theories. For this, runoff and erosion distribution in the spatial scale is evaluated to design and implementation of conservation technique at the watershed scale (Kumar et al. 2017). Conventional methods for measurement of soil erosion and runoff are costly and take much time. Moreover, it is having limitations because of the intricacy of relations and the generalization of the results is difficult. It is therefore, required to use some appropriate methods to assess these hydrological parameters of the watershed. Watershed models are currently used to quantify these parameters using geographical information system and remote sensing (Thakur et al. 2016). There are various hydrologic models available that can be used to represent and simulate hydrological processes at the watershed scale. The basic aim of these hydrological models is to understand the hydrological scheme for the sustainable management of water and land resources and to protect our ecosystem. These models have been proved to be useful analytical tools for understanding and finding solutions through changing land-use and applying best management practices (BMPs). The application of BMPs is helpful in reducing the damaging effects of runoff and soil erosion on the productivity of land and quality of water due to eroded sediments and essential nutrients. The modeling study supports for efficiently developing and managing soil and water resources (Narsimlu et al., 2015; Kumar et al., 2017; Kumar et al., 2018b). The research of these models showed that in every scenario, no single model performed well in every situation to simulate runoff (Bingner et al. 1989). Almost all of the hydrologic models are designed for simulation of hydrologic processes of watersheds and are not easily applied to every situation. The SWAT model better evaluates hydrological variations in space and time for large watersheds in comparison to other models. It has been used intensively for simulation of streamflow, soil, nutrient and pesticide yield at watershed scales (Tyagi et al., 2014; Kumar et al., 2017; Kumar et al., 2018b). Moreover, SWAT reflects the effects of management practice on hydrological and environmental processes (Chaubey et al., 2010). SWAT is also used for impact assessments of land cover/ land use and climatic change under different scenarios (Kumar et al. 2018a). Therefore, it is important to evaluate the performance of the SWAT model for its future use in the region to simulate hydrological parameters under the conditions that prevail in Shivalik foot-hills. STUDY AREA The present study area is upper Patiala-Ki-Rao catchments lying on Shivalik hills of Panchkula district of Haryana and SAS Nagar district of Punjab States of India and situated between 30°.79' N and 76°.81' E at lower left and 30°.84' N and 76°.87' E at upper right as shown in Fig.1. Two tributaries originate from the hilly and dense forests of Shivaliks at Panchkula, passing through the undulated forests and join together at karoran villages of District SAS Nagar (Punjab) on Shivalik foothills to create a flood plain, cross NH-21 and then NH-1 between Rajpura and Sirhind, passing through Patiala and merges into the river Ghaggar. Puri (2005) had studied the hydrological