Table of Contents

Introduction to Component 2

Characterization and assessment of the source water, the water and wastewater systems that rely on the source water, and the land or subsurface area from which the source water is derived are essential to develop goals and plans for source water protection. The primary outputs of this component are a comprehensive Source Water Protection Map and Source Water Characterization Report that will be used extensively in Components 3 and 4. Each of the six characterization steps provide a piece of information that is required for these two primary outputs.

This characterization has six pieces:

  1. Delineation: geographically delineate source waters and the areas of concern from which they are derived.
  2. Water and Sanitation System(s) Description: capture and analyze data on water and sanitation systems that rely on the source water within the delineated area.
  3. Analysis of Water Quality and Quantity: gather and maintain appropriate water quantity and quality data from both community source waters and WASH water points.
  4. Inventory of Contaminant Sources, Land Use Practices, and Hazards: document appropriate information about known contaminant sources, land use activities, and other relevant information from the delineated area(s) of concern.
  5. Climate Resilience Assessment: assess the source water’s susceptibility to climate change and document how water quality, quantity, or both could change due to climatic factors and how these changes will inform the action plan.
  6. Inventory of Laws, Policies, and Regulations: compile a list of laws, policies, and regulations concerning land use management and other relevant activities that apply to the source water protection area.

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Delineation

<aside> ℹ️ Task requirements: 1 SWP Team Member, 1/2 a day to 1 day

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<aside> ✅ Output: Physical map or digital file of catchment area in a GIS program

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Watershed delineation is the process of identifying the geographic area that contributes to water flow into a specific point, often a water body such as a stream, river, lake, or ocean. The term "watershed" refers to an area of land that captures rainfall and other precipitation, then channels this water into a common outlet. This is often a lower point in the landscape, where the water flows out of the watershed.

In the process of watershed delineation, a boundary line is drawn that defines the surface area from which all the water will flow to the selected outlet point. This can be a complex process that takes into account the topography of the area, soil characteristics, vegetation cover, and even man-made structures that could impact the flow of water.

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Delineation is can carried out using geographic information system (GIS) technology, digital elevation models (DEMs), or topographic maps. Any of these can be used to calculate the direction of water flow and to identify the highest points that define the watershed boundary.

The identified watershed can vary in size. It can be large (like the Mississippi River basin that extends across multiple U.S. states) or small (like a local stream or drainage ditch).