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HYDROGEOMORPHIC CRITERIA IN GROUND WATER MODELLING 
S.K. Subramanian 
NRSA, Hyderbad 
INTRODUCTION 
Surface water and ground water are the two major 
components of the hydrologic system with different but 
interrelated geoenvironmental characteristics. Even 
though, many parameters are essential for identifying 
the potential and quality aspects, the geomorphology 
plays an important role in identification, classification 
and monitoring of the ground water resources. 
Conjunctive use of both surface and ground water 
resources in any hydrologic unit like watershed or a 
river basin, over a heterogeneous terrain, can lead to 
significant economic advantages. The optimal ground 
water development, on a sustainable basis, needs to have 
an integrated modelling approach where hydrogeo 
morphology plays a lead role. Based on the landform 
characteristic, the variation occurs both on surface and 
subsurface which can be measured on the field and by 
using remote sensing techniques. Even though the field 
measurements in exploration, exploitation and 
monitoring of water resources are more accurate, the 
time and cost involved is a question of debatable area. 
Therefore, it is necessary to adopt a mechanism using 
indirect methods and evaluate the same in the field 
wherein an acceptable accuracy can be achieved. 
PARAMETERS INVOLVED 
The quantitative method in assessing the ground 
water resources depends on the following parameters 
viz. Geology and Soils covering the detailed study of 
geological formations on various litho units, structural 
features, aquifer geometry, hydrological characters of 
formation, soil type and their role, bore hole lithologs; 
Hydrometeorology on the assessment of weather cycle, 
climate, rainfall, évapotranspiration, relative humidity, 
soil moisture, wind velocity and climatic influences over 
water resources. Hydrogeological characters like aquifer 
types, flow patterns, water level fluctuation, deter 
mination of aquifer transmissivity, storativity, specific 
capacity of aquifer and the hydrogeomorphological 
aspects on the topography, drainage, slope aspects and 
gradient, hydrogeomorphic unit, hydrological 
significance of geomorphic features are important in 
ascertaining the quantitative potential of ground water. 
However, for assessing the quality, the hydrogeo 
chemical and hydrogeophysical characters of the aquifer 
are necessary. 
Remote Sensing technology with its recent 
developments in imaging sensors has got the capability 
to acquire timely and up to date data regarding the 
terrain conditions for extracting the information on 
ground water potential zones. This is mainly due to the 
fact that it can furnish information on multiple aspect of 
terrain like geomorphology, geology, physiography, 
vegetation cover, soils, drainage etc. Further relief, slope 
and aspects of various land forms play a dominant role 
in assessing the potential and to some extent quality of 
ground water. The morphometric data from remote 
sensing and field become vital information in ground 
water assessment models. 
Steps involved in Modelling of Ground Water 
A ground water model is a simplified represen 
tation of the actual geohydrological system. It has two 
components - first being the flow characteristics 
focusing on the recharge characteristics, fluctuation of 
water level due to draft, precipitation etc. which means 
the potential aspects alone. The second part deals with 
the chemical components, flow especially the pollutant 
transport in a medium. Different mathematical models 
are used to simulate the ground water condition keeping 
in view of the inter related parameters and to forecast 
the head, flow characteristics in former case and water 
quality changes that can occur under different types of 
stress imposed over a region in the latter case. Models 
can provide valuable directions in solving specific 
problems like - 
a) Estimation of recharge from canals, tanks, 
reservoir, field ponds etc. 
b) Monitoring the aquifer conditions for different 
rates of pumping 
c) Assessing the inter-relation network of wells 
d) Assessing the interaction between inter watershed 
boundary and their aquifer condition and their flow 
condition.