HYDROLOGIC DATA

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HYDROLOGIC DATA
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BACKGROUND

• Analysis and synthesis of data is required to
  perform any hydrologic computation.
• The engineer needs to
• Identify and define the data needed for an
  application
• Identify sources of data
• Acquire data and review the data for accuracy

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COLLECTION AND COMPILATION OF DATA
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Site investigation and field surveys

• Field surveys are the primary sources of
  hydrologic data
• Typical data include drainage boundaries, flow
  directions, high water marks, assessments of the
  performance of nearby drainage structures,
  assessments of stream stability and scour
  potential, significant changes in land use, etc.

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Federal Data Bases

• U.S. Geological Survey (USGS)
• U.S. Army Corps of Engineers
• National Weather Service (NWS)
• U.S. Soil Conservation Service (SCS)
• Federal Emergency Management Agency
• Environmental Protection Agency

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State and Local Agencies

• Environmental Protection Agencies
• State Highway Departments
• Planning Agencies
• Universities

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Other Data Sources

• Certain types of data are needed so frequently
  that some state agencies have compiled them into
  a single drainage manual.
• Historical Records or accounts are recorded in
  newspapers, magazines, or by state historic
  societies or universities.

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The National Water Data Exchange (NAWDEX)

• Was created to assist users of water data in the
  identification, location, and acquisition of
  needed data
• Maintains two major files
• Water Data Sources Directory
• Organizations that collect data
• Types of water data collected and availability
• Master Water Data Index

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Streamflow Data

• Network of Streamgages
• USGS compiles and publishes the data in Water
  Supply Papers
• WATSTORE Water Data Storage and Retrieval System

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Precipitation Data

• Climatological data are collected by the National
  Weather Service
• NWS Raingage Network
• Weather Service Forecast Offices
• River Forecast Centers
• The National Climate Data Center (NCDC) collects
  and processes, and disseminates data

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Soil Data

• The Natural Resources Conservation Service (NRCS)
  formerly the SCS, publishes generalized soil maps
  for each state and a detailed soil map for each
  county.
• SCS County Extension Offices can supply the soils
  data.

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Land Use Data

• Form of Data - Topographic maps, aerial
  photographs, zoning maps, and Landsat Images
• Sources of Data - State, Regional or municipal
  planning organizations, U.S. Geological Survey,
  Natural Resource Economic Division

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Adequacy of Data

• How Accurate is the Data?
• Will it meet my purpose?
• Can I add to the data base?