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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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