Analytic Hierarchy Process for Targeting and Designing Rainwater Harvesting Structures
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Date
2019
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DIVISION OF AGRICULTURAL ENGINEERING ICAR-INDIAN AGRICULTURAL RESEARCH INSTITUTE NEW DELHI
Abstract
The present study was undertaken in Gambhir River watershed in Bharatpur and
Karauli districts of Rajasthan (India). The watershed was located between 26 36′
0.8″ N to 26 57′ 35″ North latitudes and 77 0′ 2″ E to 77 16′ 54″ E longitudes.
Most of the surveyed Rainwater Harvesting Structures (RWHS) in the study area
(Check Dams, Anicuts, Khadins and Ponds etc.) were in dilapidated conditions; silted
or dried up. The ground water recharge reduced while pumping (draft) steadily
increased resulting in to sharp decline of water table requiring creation of new RWHS
vis-à-vis repair and maintenance of the existing ones. Objectives of the present study
were: (i) estimating surface runoff potential of the watershed using NRCS-CN
method and Geospatial techniques; (ii) selection of most appropriate sites for different
types of RWHS using Analytic Hierarchy Process (AHP); and (iii) design of different
types of Rainwater Harvesting Structures (RWHS).
The average depth of surface runoff; estimated based on spatial variability
analysis over a period of 11 years (2007-2017), i.e. the runoff potential of the
watershed varied from 136 to 321 mm. While the runoff volume was estimated as
149.07 Million m3 with a runoff coefficient of 0.32. Site suitability analysis for
construction of different types of RWHS was attempted using RS, GIS, AHP and
Boolean logic. Nearly 75.54 km2
(13%) area was found to be very highly suitable
whereas, 114.56 km2
(19%) area was highly suitable for construction of RWHS.
About 43.77 km2
area was not suitable at all for construction of any type of RWHS.
Three types of RWHS including farm pond, check dam and percolation pond were
suggested for the given study area based on the criteria. Further, it was found that
approximately 55% area in the experimental watershed was highly suitable for
construction of farm ponds. About 308.53 km2
(53%) area was highly suitable for
constructing percolation ponds. A total number of 15 check dams were proposed for
construction at appropriate locations as identified in this study. In the selected microwatershed for detailed planning (MW 36) out of 59 micro-watersheds in the main
watershed; about 7 farm ponds, 2 check dams and 1 percolation pond; were identified
and mapped. The locations of 3 different types of structures were randomly selected
in MW 36 for detailed hydrologic and hydraulic design following the scientific design
procedures. The designed dimensions were computed and their drawings finalized
corresponding to the designed runoff. The present research work demonstrated that
the AHP was one of the most comprehensive decision-making techniques for site
selection of different types of RWHS incorporating a large number of suitability
criteria. The study has aptly demonstrated that AHP in combination with other
techniques like Boolean logic, RS and GIS can be successfully employed for sizing
and siting of different types of RWHS.
Keywords: Analytic Hierarchy Process (AHP), Rainwater Harvesting Structures
(RWHS), Remote Sensing (RS), Geographical Information System (GIS) and Fuzzy
Logic.
Description
t-10123
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