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The report presents a systematic procedure for the computation of evaporation from lakes. Water balance of a lake depends upon the relative importance of various inputs and outputs to and from the lake. In Indian conditions, evaporation loss constitutes one of the major outputs from a lake and as such, the water regime of a lake and yield are influenced by it. In order to conserve and use the water, there is an urgent need for a first hand reasonable accurate estimate of its water balance.

The report provides an account of the findings of water quality studies of Lake Nainital and surroundings. Even though quite a few water quality investigations have been conducted by other researchers, they were more focused on biological aspects and overlooked the hydrological aspects. Further, not all of the earlier studies on Nainital incorporated the groundwater quality aspects, which are essential to establish the background values that can be ascribed to the geology of the region. Only after establishing these, the pollution levels can be assessed.

The report presents the effect of non hydrostatic pressure distribution on dam break flood wave movement. Dam break flood moves with non-hydrostatic pressure distribution in the vertical direction. However, almost all the mathematical models for dam break flows use Saint-Venant equation, which presume hydrostatic pressure in the vertical direction. In this report, an attempt has been made to use Boussinesq equations in the mathematical model. 

Article Courtesy : Reuters AlertNet
Written by: Nita Bhalla

NEW DELHI (AlertNet) - Floods triggered by heavy monsoon rains have killed more than 50 people and displaced almost half a million more in India's south and northeast, say government officials.

Overflowing rivers and reservoirs have inundated low-lying villages mainly in India's oil and tea-rich state of Assam, but also on the opposite side of country in the southwestern coastal state of Kerala.

Flood-affected people sit in a damaged hut
as they wait for relief supplies in Lakhimpur
district, in India's northeastern state of Assam.
FILE PHOTO, July 2009. REUTERS/Stringer

According to the ministry of home affairs, almost one million people have been hit by the floods, forcing almost half a million to leave their water-logged villages and seek shelter in government relief camps.

Mountainous Assam, where five people have drowned, has been the worst-affected with 13 out of 27 districts hit by flooding, including Kokrajhar, Lakhimpur, Baksa and Bongaigaon.

Article and Image Courtesy: Consortium for DEWATS Dessemination Society

The July edition of e-Disha published by the Consortium of DEWATS Dissemination Society (CDD) has the following highlights:

In this study, Clark’s model has been used for derivation of one-hour unit hydrograph for a catchment. The design flood estimate has been obtained using the calibrated parameters of the Clark model together with the time-area diagram corresponding to a 48-hour design storm, which has been temporally distributed and critically sequenced as a single bell, giving due consideration to the ordinates of the unit hydrograph.

The report examines the effect of periodicity in the rainfall records on the water availability of Damanganga basin in Nasik and Thane districts of Maharashtra. Based on the rainfall-runoff record of a shorter period, runoff series for a longer period is developed using a water balance model. The per cent deviation in water availability estimations computed using short term wet and dry records from the complete records is examined. The effect of length of time-series on the water availability estimates is also studied.

In this report, a mathematical model capable of computing the flow depth and discharge in each of the branched flows is developed using gradually varied flow equations. This model can handle three flow situations viz. temporary flow diversion, a cut-off channel and a single river island. Computational capability of the model is increased to handle irregular cross sections of a river.

In the present report a mathematical model has been developed for the study of stream aquifer interaction in multilayered system viz. a three-aquifer system, in which aquifers are separated by aquitards, considering varying stream-stage and vertical flow through aquitards. The model enables the computation of rates of recharge to the upper aquifer and exchanges of flow among aquifers along with the spatial and temporal distributions of piezometric heads in the aquifers.

Organizer: Centre for Science and Environment

Venue: Centre for Science and Environment, 41 Tughlakabad Institutional Area, New Delhi

Description:

The water and sewage management in cities will determine the quality of life in urban India. Most cities are today water stressed, unable to cope with the water demand of the growing urban populations and to treat the resulting wastewater.