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REFINEMENT OF WATERSHED BOUNDARIES AS PER CENTRAL
COMMITTEE GUIDELINES FOR MAHARASHTRA STATE

A. Introduction

Need for refinement of watershed boundaries;
• Many of existing watershed boundaries follows the river as boundary
which does not fulfill the concept of single pour point
• Watershed (AISLUS) as development unit of large area is improper for
planning activities.
• Existing area of GSDA watershed ranges from 200 to 300 sq.km.

• Due to development processes like number of major and minor water-
bodies are constructed.
• Existing watershed boundaries are use for subsurface flow analysis,
groundwater estimation and water conservation etc.
• With the advancement in the satellite technology, the resources
mapping on micro-level scale is possible, using this technology the
refinement of watershed boundaries is proposed.

B. Objective

• Formation of committee as per GR for setting up the methodology
• Refinement of watershed boundaries as per the central committee
guidelines.

C. Methodology

Watershed boundary is to be delineated considering Single downstream
outlet (point) of drainage network. Delineation of hydrologic features must
be based on land surface, surface-water flow and hydrographic features.
Hydrologic unit boundary should cross the stream at a significant
confluence. Boundaries should not follow or run parallel to streams.
Boundaries will cross the stream perpendicular to flow at the hydrologic unit
outlet.
Delineating boundaries down the middle of the stream is to be avoided.
Delineation started from the designated outlet and proceeds to the highest
elevation of land dividing the direction of water flow. Higher order streams
are chose over smaller tributaries for delineating hydrologic unit. Hydrologic
units divided at reservoir outlet, if the upstream drainage-area size is
appropriate for the hydrologic unit level or submerged morphological
features.In highly dissected/hilly area high resolution satellite will be use.

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MRSAC,Nagpur ©®
MRSAC,Nagpur ©®