PROGRAMS AND PLANS--Computer Storage of Urban Unit-Values Data In Reply Refer To: October 8, 1981 EGS-Mail Stop 415 SURFACE WATER BRANCH TECHNICAL MEMORANDUM 82.01 Subject: PROGRAMS AND PLANS--Computer Storage of Urban Unit-Values Data The purpose of this memorandum is to emhasize the need for timely computer storage of unit-values data which are collected as part of hydrologic studies in urban areas. Many hydrologic processes in urban areas are not well understood. One of the reasons for this lack of understanding has been a lack of available data. There are presently a large number of projects in the U.S. Geological Survey (USGS) which are collecting data in urban areas. The availability of these data to a wide spectrum of investigators will help the scientific community to more quickly gain insights into urban hydrologic processes. A major goal of the USGS urban studies program is to develop an urban-hydrology data base. A key to this development is the entry of urban data into WATSTORE. Generally, daily-values and water-quality data have been entered into WATSTORE in a timely manner. The unit-values data have not been entered in such a timely manner. Much modeling of urban systems requires unit-value data. Studies which are primarily concerned with the investigation of peak flows may require unit- value data for only a few of the larger storm events. Studies which are concerned with the water-quality of urban runoff may need unit-value data for all runoff events. Unit-values data for precipitation and runoff should be entered into WATSTORE for selected significant events for studies where water-quality data are not collected. For studies where water-quality data are collected, unit-values data for all monitored runoff events should be entered into WATSTORE. It is important that unit-values data be processed and entered into WATSTORE at least annually. If data are not entered into WATSTORE until the end of a project, other priorities may arise and the data may not be entered into WATSTORE. Another reason for entering data at least annually is that a variety of people have need for the data. An example involves those studies which are a part of the Environmental Protection Agency's (EPA) Nationwide Urban Runoff Program. EPA needs the data from those studies as quickly as possible so they can perform certain analysis in order to meet their commit- ments to Congress. 2 Your entering of unit-values data into WATSTORE in a timely manner will help you and others do their job more efficiently and effectively. Marshall E. Moss Acting Chief, Surface Water Branch WRD Distribution: A, FO "This memorandum does not supersede any existing SWB memorandum."