ESTIMATION OF WATER HARVESTING AND GROUNDWATER RECHARGE POTENTIAL OF DHATARWADI RIVER BASIN USING REMOTE SENSING AND GIS 3307
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Date
2021-08
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JAU JUNAGADH
Abstract
Morphometric analysis of the Dhatarwadi river basin revealed that, it is found
to be a 6th order drainage basin in its youth stage having dendentric type drainage pattern
in most of the area, which is free from the influence of the geological structure. The
basin is having near about flat terrain with small hillocks/inselbergs and elongated in
shape along with high permeable subsoil material under dense vegetative cover
indicating low to moderate runoff potential of the basin. There are 13 milli-watersheds
in Dhatarwadi river basin, having 3rd to 5th order drainage network. The milli watersheds are showing moderate to less structural disturbance, high permeable
geology, good vegetation cover, high infiltration, low runoff and less soil erosion
condition. All the 13 milli-watersheds are more or less elongated in shape and have low
to high relief. Among 13 milli-watersheds, the milli-watershed: 5G1D4d should be
prioritized first for applying soil and water conservation measures followed by
5G1D4e, 5G1D4h, 5G1D4k, 5G1D4j, 5G1D4g, 5G1D4c, 5G1D4b, 5G1D4a, 5G1D4i,
5G1D4l, 5G1D4m, 5G1D4f as they ranked 1st, 2nd and 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th
,
11th, 12th and 13th ranking in priority analysis.
In this study, to estimate surface runoff potential, 16 years of weather and
discharge data along with SRTM DEM imagery, soil maps, land use/cover map and
slope map were used as primary inputs for SWAT model. The weather and discharge
data were divided into calibration period (year 2002 to 2011) and validation period
(year 2013 to 2017). The global sensitivity analysis for the study area highlighted that
CN2, SOL_BD, GW_Delay and RCHARG_DP.gw were found as sensitive parameters.
Based on SWAT model runoff simulation, the average annual precipitation of 680.94
mm could generate 217.75 mm (186.4 MCM) runoff.
Groundwater recharge for the study area were estimated using Water Table
Fluctuation method, Krishna Rao (1970), Athavale (2003), Maheta & Rank (2017), Kumar
& Seethapathi (2002), developed linear models; Model I, Model II and non-linear; Model
III during year 2002 to 2017. The linear empirical model II (R2 = 0.828) for ground water
recharge estimation performed well than empirical model I and III during calibration
period (year 2003 – 2011). During validation period (year 2013 – 2017) the non-linear
empirical model III performed well with 0.848 R2 value. Data shown that the overall
iv
mean groundwater recharge in the Dhatarwadi river basin was estimated to be 15.09 %
(87.61 MCM) of the mean annual rainfall. Groundwater recharge estimation formulae i.e.
Athavale (2003), Maheta and Rank (2017), developed Model I and Model II were found
perfectly positively correlated to each other. The non-linear empirical model for the
ground water recharge in the Dhatarwadi river basin is proposed as; R= 0.037(P-20)1.17
.
For water harvesting site selection, AHP generated weight for criteria were
36.1%, 20.6%, 18.6 %, 13.1 % and 11.7 % for rainfall, land use/land cover, soil texture,
lineament density and slope, respectively. In study area, 66.79 % area found very high
suitable, 24.89 % highly suitable, 5.63 % moderately suitable, 0.88 % less suitable and
remaining 1.81 % area found not suitable for water harvesting sites. 25 sites for check
dam on scrubland, 52 check dam sites on crop land and 11 check dams on river bed
were possible sites identified within the Dhatarwadi river basin. 29 farm pond sites were
identified within the Dhatarwadi river basin.