Workshop on Effective Implementation of IWMP

Hydrology for IWMP

7th and 8th Jan 2013

7th and 8th Jan 2014, PUSA, New Delhi

Vaishakh PalsodkarGeo-Hydrologist, Dept. of Land Resources,

MoRD, New Delhi

Objectives

1. Understanding 1. the components of hydrologic processes2. the quantity and availability of water3. the quality of water 4. the impacts of land use and forest management

practices on water resources5. the most basic concepts of hydrologic monitoring

2. Utilizing hydrologic information resources to solve real problems

HydrologyHYDROLOGY is the science of water that is

concerned with the origin, circulation, distribution and properties of water of the earth.

Watershed /CatchmentWATERSHED, 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 storageP + R + B - F - E - T = ΔSvolumes are measured in units m3, L, ac-ft, f3, gal, or in & cm over the watershed area

Impacts of Development

50%50%10%10%10%10%

Natural Landscape Low runoff High recharge Healthy summer stream flow Natural pollutant treatment

15% 55%

Developed- High runoff, Low recharge- Nuisance flooding- Lower water tables- Low stream flow

Development Impacts on the Water Cycle

30%40%

GL

AQUIFER

AQUIFER

AQUIFER

AQUIFER

60 M

90 M

120 M

RECHARGE - RAINFALL

DRY DRY DRY

DRY DRY

DRY

IMPERVIOUS

IMPERVIOUS

IMPERVIOUS

IMPERVIOUS

Adverse Effect On Shallow Aquifers Due To Irrigation Borewells

Importance of Hydrology study•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-Basin

Sub-Watershed

Micro-Watershed at field level

Basin

Integrated approach

Development and Management of ground water is governed by various disciplinesTopographic surveyStudy of Remote Sensing DataGeomorphological studiesGeohydrological SurveyCommunity participation and ground water

budgeting Artificial recharge, Rain water harvesting and

Conjunctive use

Topographic Survey

Sound mapping and assessmentof the gradient

Peoples participation in projectprioritisation & implementation.

Rain fall Data

Area of watershed Topography

Soil types Geology

Cropping pattern Run off

Evapotranspiration Recharge

Cumulative draft for different uses

Final balance

Governing

factors

Water Budgeting/Auditing