MORPHOMETRIC AND HYDROLOGIC ANALYSIS OF BHADAR BASIN OF GUJARAT USING REMOTE SENSING & GIS TECHNIQUES 2801
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Date
2019-01
Authors
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Journal ISSN
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Publisher
JAU, JUNAGADH
Abstract
The natural resources planning and management can be successful if it is
based on the drainage basin scale. The feasible and viable techno-economic planning
for the soil and water conservation requires the hydrologic response to climate and
various land uses. Morphometric analysis of a drainage basin expresses fully the state
of dynamic balance that has been attained due to dealings between matter and energy.
Morphometric analysis based either in GIS environment or otherwise is a competent
tool for geo-hydrological studies and are very useful for identifying and planning the
groundwater potential zones and watershed management, including the whole gamut
of natural resources connected with the watershed. It becomes necessary to
understand the topography, erosion status and drainage patterns of the region. The
SWAT model is the tool to assess the water balance components of the hydrological
cycle like rainfall, runoff, evapotranspiration and groundwater recharge under given
land use, management and climate. The runoff and groundwater recharge assessment
are very useful for the water resources development and planning.
This study was undertaken for the Bhadar River basin divided into 16
watersheds and total drainage area of 7330.40 km2
. Morphometric analysis, such as
linear, aerial and relief aspects of the Bhadar River basin has been done with the help
of remote sensing and GIS techniques. The climatic, discharge and sediment yield
data were divided into calibration period (1981-2000) and validation period (2001-
2010). The climatic and discharge data, sediment data, SRTM-DEM imagery, soil
maps and land use/cover classification from LISS IV imagery are used as primary
inputs for SWAT model. The SWAT model was used to assess the hydrologic
response of the basin after sensitivity analysis, calibration and validation. In this study
SWAT model was developed for sediment yield simulation at the outlet of the basin
and this model applied to the every watersheds of basin for the estimation of sediment yield. The watershed prioritization was made using the morphometric parameters and
sediment yield from all watersheds. The groundwater recharge was estimated using
water table fluctuation and SWAT Model and compared. Hydrologic analysis is
an analysis of interrelated components, including the processes of precipitation,
evaporation, transpiration, infiltration, groundwater flow, streamflow, sediment yield
etc., in addition to those structures and devices that are used to manage the hydrologic
system. The capabilities of remote sensing and GIS techniques are explored in this
study to simulate sediment yield in the basin. The ground water recharge was also
estimated using empirical equations. Precipitation measured at 37 stations over
1981−2010 is used as an input dataset to establish hydrologic analysis. 30 years of
climatic and discharge data along with different remote sensing imagery and soil map
were also used. The empirical model was developed and proposed to assess the
groundwater recharge using the seasonal rainfall data. The performance indices like
NSE and goodness of fit were used in the modeling to assess the accuracy in the
predictions.
The river basin is designated as 7th order basin. The 1
st order streams are
mostly dominating the basin. The moderate drainage density indicates that weak
subsurface material and belongs to medium texture. The study reveals that the basin
has less elongated to elongated shape and associated with steep ground slopes. The
ranges of Rb are high as mean Rb of the basin is 5.38, and it has been characterized
by the influences of underlying structures and lithology. Relief having a value of
0.303 km indicates low gravity of water flow as well as infiltration and high runoff
conditions. The watershed 5G1B15 should be treated first while 5G1B4 at last.
Highest priority indicates the greater degree of erosion in the particular watershed and
it becomes potential candidate for applying soil conservation measures first.
The developed soil theme map shows that clay and fine soil are dominating in
the Bhadar river basin. The land use/cover analysis shows that agricultural land is
dominating in the basin. The sediment yield obtained from different watershed using
SWAT model also gives the same highest priority to watershed 5G1B15 having
highest sediment yield among all watersheds. The performance of SWAT model is
satisfactory in terms of different performance indices such as NSE and goodness of fit
for calibration(NSE=64.6%, R2
=0.762) and validation(NSE=68.5%, R2
=0.798).
SWAT model provides a better description of water balance of the watershed. The
average annual rainfall, runoff, evapotranspiration, percolation to shallow aquifer and
recharge to deep aquifer in the basin are 569.3 mm, 197.19 mm, 244.6 mm, 111.64
mm and 5.58 mm respectively. The annual average runoff is 36.37% of the average
annual rainfall. The average annual sediment yield during calibration and validation
periods are 14.13 t/ha and 19.40 t/ha. Among the developed models, the non-linear
empirical ground water recharge model as R = 1.642(P – 230.054)0.583 (with
NSE=86.59%, where R and P are the seasonal groundwater recharge, mm for the
seasonal rainfall amount, mm of P) was found best. Performance of SWAT, a
physically based model and empirical models were compared to simulate the ground
water recharge of the Bhadar river basin. The best fit empirical model performs better
than and SWAT model (NSE = 74.94%, R2
=0.898).