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This document is intended to provide the user of Q3 Flood Data produced by the Federal Emergency Management Agency (FEMA) with an overview of the data files. Additional information in greater depth may be found in the Q3 Flood Data Specifications document.

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This document is intended to provide the user of Q3 Flood Data with detailed information regarding the contents of the Q3 Flood Data files. An overview of the Q3 Flood Data product maybe found in the Q3 Flood Data User Guide.

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This document is intended to provide the user of Q3 Flood Data with detailed information regarding the contents of the Q3 Flood Data files. Q3 Flood Data are developed by scanning the existing hardcopy FIRM to create a raster product suitable for viewing or printing and vectorizing a thematic overlay of flood risks. Vector Q3 Flood Data files contain only certain features from the existing hardcopy FIRM.

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Flood maps are a vital part of a floodplain management program, so it is important to understand how the maps are made and to be familiar with the information that is available within the accompanying flood study. This PDF technical document provides an overview of flood study terms and how studies and maps are prepared.

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The traditional design of storm drainage systems has been to collect and convey storm runoff as rapidly as possible to a suitable location where it can be discharged. As areas urbanize this type of design may result in major drainage and flooding problems downstream. Under favorable conditions, the temporary storage of some of the storm runoff can decrease downstream flows and often the cost of the downstream conveyance system. Detention storage facilities can range from small facilities contained in parking lots or other on-site facilities to large lakes and reservoirs. This PDF file provides a general design criteria for detention/retention storage basins as well as procedures for performing preliminary and final sizing and reservoir routing calculations.

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This PDF file contains documentation on how to select Manning's Roughness Coefficient. Most hydraulic computations related to indirect estimates of discharge require an evaluation of the roughness characteristics of the channel. This document contains photographs and data for a wide range of channel conditions that can be used to select roughness coefficients for other natural channels.

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Most hydraulic computations related to indirect estimates of discharge require an evaluation of the roughness characteristics of the channel. This document contains photographs and data for a wide range of channel conditions that can be used to select roughness coefficients for other natural channels.

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The NRCS National Engineering Handbook (NEH) is intended primarily for Natural Resources Conservation Service (NRCS) engineers and technicians. It presents material needed to carry out NRCS responsibilities in natural resources conservation and flood prevention.

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This files contains lecture notes from the University of Texas on detention pond design.

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This file contains lecture notes from the University of Texas on design storm development.

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This file contains lecture notes from the University of Texas on culvert design.

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This design manual provides a comprehensive and practical guide for the design of storm drainage systems associated with transportation facilities. Design guidance is provided for the design of storm drainage systems which collect, convey, and discharge stormwater flowing within and along the highway right-or-way. Methods and procedures are given for the hydraulic design of storm drainage systems. Design methods are presented for evaluating rainfall and runoff magnitude, pavement drainage, gutter flow, inlet design, median and roadside ditch flow, structure design, and storm drain piping. Procedures for the design of retention facilities and stormwater pump stations are also presented, along with a review of urban water quality practices. A summary of related public domain computer programs is also provided.

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This document provides comprehensive culvert design material. Culvert design methods are presented for both conventional culverts and culverts with inlet improvements. Storage routing techniques are included which permit the designer to account for ponding effects upstream of the culvert. Unique culvert applications, erosion and sediment control, debris control, structural aspects, and long span culverts are discussed. Inlet control, outlet control, and critical depth design charts, are included for a variety of culvert sizes, and shapes, and materials. Dimensionless culvert design charts are also provided for the design of culverts.

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This document provides estimation of Green-Ampt Infiltration Parameters used in StormNET.

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This chapter of the Engineering Field Handbook presents seven tools or procedures to use in the evaluating the hydrology of potential wetlands. Each tool is used in one or more states to assist in the determination of wetlands. These tools are analytical techniques that can be used to supplement the documentation of wetland hydrology determination.

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This handbook describes the requirements for building a pond. It is useful to the landowner for general information and serves as a reference for the engineer, technician, and contractor.

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In response to legislative authorities of 1944 and 1954, the Natural Resources Conservation Service (NRCS), formally the Soil Conservation Service (SCS), began the development of a Hydrology Guide for use in watershed planning. This effort became Section 4 "Hydrology" of the National Engineering Handbook. This development created the SCS Runoff Curve Number Equation. This paper explains the development of the relationship of Ia to S.

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Lag time, defined as the time from the centroid of rainfall excess to the centroid of direct runoff, was evaluated for over 50,000 rainfall-runoff events in 168 small watersheds in the United States ranging from 0.243 to 3,490 acres. In most watersheds a stable value of lag time was observed for the larger storms, with peak flow the variable that best showed this tendency. The watersheds were divided into groups to explain the variation of lag time between watersheds. The groups that had a significant effect in the regression equation were geographical regions, watershed management practices, and the stability of the lag time value for the bigger storms. Separation of watersheds by land use and hydrologic behavior did not significantly improve the regression analyses.

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Design rainfall-runoff hydrology and environmental impact analysis draws heavily on the Curve Number method. The centerpiece of it is the coefficient "Curve Number", a measure of a watershed's hydrologic response potential, and usually selected from handbooks based on soils, cover, and land use.

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Event rainfall depth, runoff depth, and periodic cover density measurements were taken for a total of 21 plots (2m x 2m) at 5 different locations on the National Science Foundation Jornada Long-Term Ecological Research Site in southern New Mexico. Runoff properties are characterized by plot, plot group, and site using Curve Number (CN) analysis.

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The secondary influences on direct runoff depth are studied for a number of small agricultural watersheds in the United States. A variation of Curve Number function is used as a basis for primary rainfall depth response. Using 1830 events from 25 small watersheds with effective rainfall greater than 1.00 inch, the effects of prior rainfall (including initial abstraction), intensity, and storm distribution (pattern index) on departures from the fitted rainfall effects are evaluated.

This documentation contains information about the National Flood Frequency.