Water availability and water scarcity in a river basin are influenced by the geomorphological processes occurring within a river basin. Therefore, quantitative evaluation of the river basin shape provides a crucial lead in assessment of the impact of geomorphological processes on the hydrology of the basin. Arkavathy river basin has been selected for the present study. The basin with an annual average rainfall of 874.87 mm is a persistent water scarce basin located in Cauvery river basin in south India. The basin has been subjected to rapid urbanization due to which there is an increased water demand over a period of time. Hence, to tackle the growing water scarcity and reoccurrence of droughts in the basin, an attempt has been made in the present study to investigate and understand the basin morphometry and derivation of hypsometric curve of Arkavathy river basin using remote sensing (RS) and geographic information system (GIS) techniques. Quantitative evaluation of basin morphometry has been made, and the impact of basin morphometry on the peak runoff and flooding in the basin has been assessed. The basin hypsometric curve has aided in assessment of the erosion status of the basin and its impact on the risk of sedimentation on water bodies. The morphometric parameters and hypsometric curve are then analysed to investigate the potential impact of the basin morphometry on the water availability and water scarcity afflicting the basin.

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Nearly 4 million visitors enjoy the splendor of Yosemite National Park each year, with over 22,000 visitors on an average day during the peak season. Unseen by these visitors is the infrastructure necessary to support a small city. U.S. National Park Service (Park Service) staff are responsible for the operation and maintenance of approximately 34 miles of wastewater collection system, 3 major sewage lift stations, 4 major grease interceptors, and a 1 million gallon-per-day tertiary wastewater treatment plant serving Yosemite Valley, as well as numerous smaller developed areas outside of the Valley. Photograph 1 -Yosemite National Park, Ahwahnee MeadowPark engineering and utilities staff face unique challenges in operating and maintaining this infrastructure. Increased visitation and changing use patterns require Park staff to continually adjust and adapt. Much of the park's sewer infrastructure dates from the 1930's, and funding for large capital projects requires Congressional approval and an extraordinary level of public review. Maintenance WEF/CWEA Collection Systems 2002 Conference and repair schedules are hampered by access during the peak tourist season and by weather during much of the remainder of the year. Many of the park concessionaire employees are seasonal, and require re-education on proper system use (i.e grease management) each year. Visitors often misuse park restrooms for garbage disposal. Over-riding all of these engineering, administrative, and operational concerns are the consequences of a significant sanitary sewer overflow (SSO) discharging to the Merced River -a designated National Wild and Scenic River.A catastrophic flood in January 1997 highlighted the vulnerabilities of the sewer infrastructure. Several critical elements of the collection system and interceptor from Yosemite Valley to the El Portal Wastewater Treatment Facility were destroyed. Park Service staff responded with a fast-track designbuild project that replaced the damaged pipelines, and began a concerted effort to upgrade the entire collection system. Concurrently, the Park Service has adopted the Merced Wild and Scenic River Plan and the Yosemite Valley Plan to guide future land use decisions in the Valley.In the past year, the Park Service has launched a comprehensive and systematic program to mitigate factors that might result in a sewage discharge to the Merced River. The program addresses capacity, management, operations and maintenance of the Yosemite Valley and El Portal wastewater collection systems. This aggressive program encompasses four main elements: condition and capacity assessments; spill prevention and response planning; pre-treatment, including grease and garbage management; and public education.A review of specific program elements and lessons learned in addressing the unique challenges of the national park environment provides a strong foundation for compliance with pending federal and state SSO regulations.

This paper describes the process of evaluating disinfection alternatives to replace the chlorine gas disinfection system at the El Portal Wastewater Treatment Facility (WWTF) that serves Yosemite National Park, using the Value Analysis process. The disinfection alternatives considered included ozonation, sodium hypochlorite, and UV disinfection.Disinfection options were evaluated using the Value Analysis approach. The goals of the VA process were to satisfy all of the objectives of the project, add value to the project, and to reduce costs where possible within the project goals. The options were evaluated based on ability to minimize disinfection by-products, protection of the environment and public, improved safety for Park staff, and the cost of the system. The paper also highlights some of the major design issues applied to achieve the required effluent criteria and to minimize impact on existing plant operation during construction of new facilities.