Updating Rainfall Intensity Duration Curves in the Northeast for Runoff Prediction

摘要

Predictions of precipitation events are used in the design of conservation practices, erosion and sediment control structures, stormwater management, concentrated animal feeding operation regulations and in many other civil engineering structures involving hydrologic flows. The Northeast Regional Climate Center (NRCC) has updated and made available sound data that will assist in estimating expected rainfall amounts under varying climatological conditions. This update replaces data developed from a limited time period in the early 1960s. Gridded 100%, 50%, 20%, 10%, 4%, 2%, 1%, 0.5%, and 0.2% chance of recurrence (1, 2, 5, 10, 25, 50, 100, 200 and 500-year return period) precipitation amounts were computed for durations of 5, 10, 15, 30, and 60 minutes; 1, 2, 3,6,12 and 24 hours and 1, 2, 4, 7, 10 days. To utilize the Natural Resources Conservation Service (NRCS) runoff models, grid-specific 24-hour rainfall distribution curves were also developed based on the interpolated daily and hourly return period precipitation amounts and region specific n-minute extreme precipitation ratios. Runoff calculations depend on both the precipitation amounts and the intensity of the storm event in relationship to the time of concentration. This paper presents this data, explores the website where it is available and gives example changes in runoff using the updated data.