Workshop on Effective Implementation of IWMP 7th and 8th Jan 2014, PUSA, New Delhi Hydrology for IWMP 7th and 8th Jan 2013 Vaishakh Palsodkar Geo-Hydrologist, Dept. of Land Resources, MoRD, New Delhi

Objectives Understanding the components of hydrologic processes the quantity and availability of water the quality of water the impacts of land use and forest management practices on water resources the most basic concepts of hydrologic monitoring Utilizing hydrologic information resources to solve real problems

Hydrology HYDROLOGY is the science of water that is concerned with the origin, circulation, distribution and properties of water of the earth.

Watershed /Catchment WATERSHED, or CATCHMENT, is a topographic area that is drained by a stream, that is, the total land area above some point on a stream or river that drains past that point. The watershed is often used as a planning or management unit. Natural environment unit.

Watershed Hydrology Physical Hydrology (Rainfall, Topography) Watershed Water Cycle (infiltration, sedimentation) Large scale assessment, planning Human Impacts on Water Resources

Physical Hydrology (Watershed Water Cycle)

Water Cycle Due to deforestation, negative impacts are carried downstream in the form of eroded sediments or flooding. Poor agricultural land management activities like excess fertilizer application convey negative impacts to downstream areas and may change the soil pathology

Watershed Water Cycle Based on the conservation of mass: Input – output = change in storage P + R + B - F - E - T = ΔS volumes are measured in units m3, L, ac-ft, f3, gal, or in & cm over the watershed area

Impacts of Development

Development Impacts on the Water Cycle 40% 30% 55% 10% 15% 50% Natural Landscape Low runoff High recharge Healthy summer stream flow Natural pollutant treatment Developed High runoff, Low recharge - Nuisance flooding - Lower water tables Low stream flow

Adverse Effect On Shallow Aquifers Due To Irrigation Borewells RECHARGE - RAINFALL GL DRY DRY DRY AQUIFER IMPERVIOUS DRY DRY AQUIFER IMPERVIOUS 60 M DRY AQUIFER IMPERVIOUS AQUIFER 90 M IMPERVIOUS 120 M

Importance of Hydrology study Micro-Watershed at field level In planning stage it helps to assess the available water Plan and locate your structure as per the hydrologic assessment. Water budgeting Link micro- watershed plans with higher-level watershed or plans Sub-Watershed Sub-Basin Basin

Integrated approach Development and Management of ground water is governed by various disciplines Topographic survey Study of Remote Sensing Data Geomorphological studies Geohydrological Survey Community participation and ground water budgeting Artificial recharge, Rain water harvesting and Conjunctive use

Topographic Survey Sound mapping and assessment of the gradient Peoples participation in project prioritisation & implementation.

Water Budgeting/Auditing Rain fall Data Area of watershed Topography Soil types Geology Governing factors Cropping pattern Run off Evapotranspiration Recharge Cumulative draft for different uses Final balance