Using Computer-simulated hydrological model(SWAT) to

estimate the ground-water recharge due to rainfall

Presented by - Dhiraj Jhunjhunwala 13BCL0213 Shubham 13BCL0037

Prateek Aggarwal 13BCL0099 Ramit Raunak 13BCL0259

Acknowledgement

We would like to express our heartfelt gratitude towards our guide Prof. Dilip Kumar Barik who provided insight and expertise that greatly assisted this project. At last, we would like to thank our Programme Chair, Prof. Santha Kumar & our esteemed faculties of Civil Engineering Department, SMBS . Dhiraj Jhunjhunwala Prateek Aggarwal Shubham Ramit Raunak

Statement of Problem

Estimation of Ground-water recharge by the water-balance approach due to rainfall in less

precipitous terrains

Region of Interest

SOFTWARES USED:

• ArcSWAT • QGIS• ArcGIS

SWAT Model

• SWAT (Soil & Water Assessment Tool) is a river basin scale model developed to quantify the impact of land management practices in large, complex watersheds.

• SWAT is a public domain model actively supported by the USDA Agricultural Research Service at the Grassland, Soil and Water Research Laboratory in Temple, Texas, USA.

• SWAT can be considered a watershed hydrological transport model. This model is used worldwide and is continuously under development.

Water-Balance Equation• A general water balance equation is:

P = Q + E + S

Where,P is PrecipitationQ is RunoffE is EvapotranspirationS is the change in storage (in soil or the bedrock)

SCS Hydrological Model• The runoff curve number (also called a curve number or

simply CN) is an empirical parameter used in hydrology for predicting direct runoff or infiltration from rainfall excess. The curve number method was developed by the USDA Natural Resources Conservation Service.

• The runoff curve number is based on the area's hydrologic soil group, land use, treatment and hydrologic condition.

• The runoff equation is:

• Where, Q is runoff ([L]; in), P is rainfall ([L]; in) S is the potential

maximum soil moisture retention after runoff begins ([L]; in), Ia is the initial abstraction ([L]; in), or the amount of water before runoff, such as infiltration, or rainfall interception by vegetation; historically, it has generally been assumed that ,

Ia = 0.2S although more recent research has found that may be a more appropriate and accurate relationship.

Methodology

• Following are the steps carried out to estimate the ground-water recharge:• Step 1: Determine the region of interest(Texas, US ), bound by the

specific set of coordinates.• Step 2: Download the DEM(Digital Elevation Model) of the Region

of Interest, geo-referencing in QGIS• Step 3: Delineate the watershed using the DEM in the ARCSWAT

interface • Step 4: LULC map was used as an input to define the HRUs, and

was clipped by the watershed boundary. (National Landset Dataset)

• Step 5: US STATSGO Soil map was input into the model, followed by the input of slope map (formulated by ArcSWAT using the DEM)

• Step 6: Weather data (precipitation & temperature) was downloaded and input into the swat model.

• Step 7: Input files were written and swat was setup for run. The model was run for 15 years (from 1995-2010), with 5 years of skip and time-step monthly.

• Step 8: Infiltration was calculated with the SWAT output data for 10 years(2000-2009)and the graph was plotted

Watershed

Watershed Boundary :

Streams & Basins:

NLCD 2011 LULC Map (downloaded from www.mrlc.gov/NLCD01_data.php)

LULC, SOIL AND SLOPE CLASSIFICATION REPORT:

Soil Classification Map (US STATSGO):

Generic land cover used in database

SWAT Model Output :

Thank You!