In this paper, a comparison is made of available rainfall data in a localized study area of Los Angeles County, California. This particular area has also been studied by the State of California Department of Water Res...In this paper, a comparison is made of available rainfall data in a localized study area of Los Angeles County, California. This particular area has also been studied by the State of California Department of Water Resources (DWR), the National Weather Service (NWS) National Oceanographic and Atmospheric Administration (NOAA), and the Los Angeles County (LAC) Department of Public Works. All three of these cited governmental agencies independently analyzed the rainfall data to identify rainfall trends for the study area, and then prepared statistical analyses in order to develop estimates of return frequencies for various peak durations of rainfall, among other items of interest to hydrologists. Additionally, these three agencies have available two different analyses of the available data, resulting in updates to their respective published works. Consequently, six different statistical analyses are available for comparison and assessment. In this paper, an examination is made of these six statistical studies and some of the differences between the various analyses are identified and explained.展开更多
Depth-duration analysis, such as accomplished for rainfall, can be useful in the analysis of infiltration of rainfall. The assessment of infiltration depth-duration in terms of return frequency is of interest. In this...Depth-duration analysis, such as accomplished for rainfall, can be useful in the analysis of infiltration of rainfall. The assessment of infiltration depth-duration in terms of return frequency is of interest. In this paper, depth-duration values of daily rainfall infiltration are estimated using the National Resources Conservation Service (NRCS) Curve Number (CN) approach for estimating daily runoff. The CN methods may be generally applicable to soils that are free draining. From the estimated history of daily infiltration, a depth-duration analysis is accomplished for all duration sizes from 1 day to 365 days. These annual outcomes are then analyzed as to a possible underlying probability distribution. For the rain gages considered, the depth-duration infiltration estimates (using the CN approach) appear to be normally distributed. From the fitted distribution, estimates of rare events of rainfall infiltration may be made, and possible linkage to earth movement events accomplished with respect to return frequency of infiltration, which in turn can aid in the design and risk assessment of fixed works involving soil water accumulation.展开更多
文摘In this paper, a comparison is made of available rainfall data in a localized study area of Los Angeles County, California. This particular area has also been studied by the State of California Department of Water Resources (DWR), the National Weather Service (NWS) National Oceanographic and Atmospheric Administration (NOAA), and the Los Angeles County (LAC) Department of Public Works. All three of these cited governmental agencies independently analyzed the rainfall data to identify rainfall trends for the study area, and then prepared statistical analyses in order to develop estimates of return frequencies for various peak durations of rainfall, among other items of interest to hydrologists. Additionally, these three agencies have available two different analyses of the available data, resulting in updates to their respective published works. Consequently, six different statistical analyses are available for comparison and assessment. In this paper, an examination is made of these six statistical studies and some of the differences between the various analyses are identified and explained.
文摘Depth-duration analysis, such as accomplished for rainfall, can be useful in the analysis of infiltration of rainfall. The assessment of infiltration depth-duration in terms of return frequency is of interest. In this paper, depth-duration values of daily rainfall infiltration are estimated using the National Resources Conservation Service (NRCS) Curve Number (CN) approach for estimating daily runoff. The CN methods may be generally applicable to soils that are free draining. From the estimated history of daily infiltration, a depth-duration analysis is accomplished for all duration sizes from 1 day to 365 days. These annual outcomes are then analyzed as to a possible underlying probability distribution. For the rain gages considered, the depth-duration infiltration estimates (using the CN approach) appear to be normally distributed. From the fitted distribution, estimates of rare events of rainfall infiltration may be made, and possible linkage to earth movement events accomplished with respect to return frequency of infiltration, which in turn can aid in the design and risk assessment of fixed works involving soil water accumulation.
