The use of precipitation data as input for conceptual hydrologic models has enhanced the need for measurements more representative of 'true' precipitation. Precipitation input to continuous watershed models is generally some form of mean basin precipitation estimate based on point measurements. Each point measurement can have large catch deficiencies due to wind, especially for solid precipitation. A brief review is made of past results from studies concerned with these deficiencies. New curves based on current studies are presented for wind-caused gage catch deficiencies for both rain and snow. The results of using gage catch correction factors to adjust precipitation input to a conceptual hydrologic model are presented.The use of precipitation measurements as a major input for conceptual hydrologic models has enhanced the need for point and areal measurements that are more representative of 'true' precipitation. Hydrologic modeling studies indicate that one of the most important factors in successful hydrologic simulation is reliable and representative precipitation data. Raw precipitation data are often converted to some form of mean basin precipitation (MBP) estimate for use in a hydrologic model. Present hydrologic models to a large degree are limited by the accuracy of the MBP estimate. Many factors influence the estimate of MBP, including density and arrangement of the network, the particular site and gage characteristics at each location within the network, methods of areal analysis utilized, basin characteristics, storm characteristics, etc. For solid precipitation the most important of all these items, however, is the gage catch deficiency due to wind [Peck, 1972]. Many studies in the past have attempted to evaluate gage catch deficiencies in terms of the causes and magnitudes of the errors [Green and Helliweli, 1972; Warnick, 1956]. In this paper a brief review is presented of some of these past results. Recent relationships for wind-caused measurement errors for both liquid and solid precipitation are presented. Finally, the results of using precipitation correction factors based on these relationships as input for a conceptual hydrologic model and a calibrated watershed are presented. REviEw OF PREVIOUS STUDIES CONCERNED WITH GAGE CATCH DEFICIENCIES Literally hundreds of articles have been published on this subject from the mid-eighteenth century to the present. Kurtyka [1953], Israelsen [1967], and Larson [1971a] have each published comprehensive literature reviews containing a total of some 1600 references in the general field of precipitation measurements. More recently, the World Meteorological Organization [1973] has published an annotated bibliography in the same subject area.Although most studies vary with one another as far as the magnitudes of gage catch deficiencies due to wind are concerned, they all reach the same general conclusions. That is,

Abstract. As our Nation's population and infrastructure grow, natural disasters are becoming a greater threat to our socie'ty's stability. In an average year, inland flooding claims 133 lives and resulting property losses exceed $4.0 billion. Last year, 1997, these losses totaled $8.7 billion.Because of this blossoming threat, the National Weather Service (NWS) has requested funding within its 2000 budget to begin national implementation of the Advanced Hydrologic Prediction System (AHPS). With this system in place the NWS will be able to utilize precipitation and climate predictions to provide extended probabilistic river forecasts for risk-based decisions. In addition to flood and drought mitigation benefits, extended river forecasts will benefit water resource managers in decision making regarding water supply, agriculture, navigation, hydropower, and ecosystems. It's estimated that AHPS, if implemented nationwide, would save lives and provide $677 million per year in economic benefits. AHPS is used currently on the Des Moines River basin in Iowa and will be implemented soon on the Minnesota River basin in Minnesota. Experience gained from user interaction is leading to refined and enhanced product formats and displays. This discussion will elaborate on the technical requirements associated with AHPS implementation, its enhanced products and informational displays, and further refinements based on customer feedback. Benefits of Hydrologic ForecastsRecent flooding events throughout the United States and the world have heightened our awareness of the devastation and strife that flooding can impose upon society and the environment. They have also made us keenly aware that extreme events will continue to occur and that structural modifications to the rivefine environment in flood prone areas are not always viable solutions. Therefore as population growth continues and people choose to live by the water, there is an ever increasing need to educate the public on flood-related hazards and to improve our predictions to support flood mitigation efforts. Likewise, drought mitigation activities can benefit from these same forecasts.Flood damages continue to accrue despite traditional mitigation measures. While the principal structural measures to reduce flood damages are reservoirs and levees, the primary nonstructural solution is a timely and accurate hydrologic forecast. However, a hydrologic forecast is only of value if it induces a response from the floodplain user that leads to an effective action. For example, when a flood warning is issued to the general public, a benefit can only be realized through evacuations, flood-fighting measures, or the shutdown of facilities to reduce potential flood losses.Benefits associated with hydrologic forecasts are attributed to 19,655

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