The area's geological, hydrological and climatic facets are studied to arrive at a series of recommendations, which not only include the type of recharge structures and their design but also their location.
The report is divided into 9 chapters which are
- Introduction
- Geo-morphological setup
- Climate and rainfall
- Surface water hydrology
- Geology and hydro-geology
- Groundwater resources
- Groundwater development and recharge possibilities
- Management strategies
- Conclusions and recommendations
Introduction
JSPL steel plant in Angul under construction, is to have a capacity of six MTPA. The total water requirement for the plant including for domestic purposes has been estimated to be 328,800 m3/day. The demand for water is going to be met by taking water from the Brahmani river through a 24.5 km pipeline. Till the pipe was laid, 5000 m3/day of groundwater was to be extracted for construction and other purposes.
Geo-morphological setup
Geo-morphologically, the area can be divided into three physio-graphic regions; a map describes these characteristics. Part of the area forms the watershed between rivers Brahmani and Mahanadi. The physio-graphic characteristics of the area provide ample opportunities for rain water harvesting as well water conservation.
The drainage here is mainly dendritic, though sometimes it is parallel in hills. The Darjanga reservoir is the main source of water and is located quite close to Angul town. An agro-climatic map of the country is given where it indicates that Orissa is under one climate zone but has 3 different types of soil.
Climate, rainfall and surface water hydrology
The average rainfall in Angul is 1266.7 mm, a major portion of which is received between June and September. Climatological data from the Indian Meteorological Department station at Angul is provided. The run-off from two micro watersheds is determined by using the Khosla formula where the monthly runoff in cm is calculated by using the figures for monthly rainfall in cm, monthly water losses in cm and mean monthly temperature of the catchment. A table provides the monthly runoff during monsoons for 14 different micro watersheds in the area. With this data, the type of water harvesting structure to be constructed to harvest 33% of the runoff during peak rains is given.
Geology and hydro-geology
A description of the geological and hydro-geological features of the area are also given. Angul district has a diverse geological sequence consisting of rocks of the Eastern Ghats belonging to the Pre-cambrian age, Iron-ore super group, Gondwana super group, Laterites to alluvial deposits of Quaternary age. These have been described in a table. A hydro-geological map of the area is also provided. A diagram providing details of the ground water levels during pre-monsoon periods is also given. It is stated that the seasonal fluctuation of depth to water level in the area is between 2 to 4m.
Groundwater resources
From the study of the area four zones were identified where ground water can be developed, this is also given in a map. Also four areas have been identified where artificial recharge can be undertaken, these areas have been plotted in a map.
Groundwater development and recharge possibilities
A series of water management strategies have been suggested. The intention of the strategies is to utilise the available runoff in the project area and to also develop ground water with feasible augmentation. Suggestions on water harvesting in the micro water shed areas are made along with designs for such harvesting structures.
Management strategies
It has been calculated that during monsoons around 10 MCM of water is available in the watershed of which 2.5 MCM water can be harnessed by constructing check-dams. Various points to be considered in choosing site for construction of artificial recharge structures are also elaborated. These include areas where salinity ingress has occurred, ground water levels are declining over a period of time etc. Thus a series of options for recharge structures are given based on factors such as runoff quantity etc.
Conclusions and reccommendations
The report, by conducting a scientific and methodological analysis of the area, has been able to provide JSPL with a series of recommendations that cater to its and also to the specifications of the area in terms of its geology, hydrology and climate.
Download the report here: