The Watershed Health Assessment Framework (WHAF) provides an organized approach for exploring the complexity of natural and human systems. A 'Use Case' uses the Map to show an important concept with an example and instructions for you to follow.
CONCEPT: Spatial Scale
- Map and Share Your Watershed Boundaries
- Why Are Watershed Boundaries Important?
- Use Case 1: Selecting the Major Watershed: Pine River Watershed
- Use Case 2: Upstream and Downstream Connections: Managing Mussels in the St. Croix River
Watershed boundaries are a challenge to understand and even more difficult to visualize or map.. until now! With WHAF's predefined boundaries and symbols you can display different watershed boundaries across spatial scales for any catchment in Minnesota in just 3 clicks of the mouse.
Step 1: Click here to open this map in a new browser window.
Step 2: Click on 'set location' tool . It will turn orange when it is 'on'.
Step 3: Click on your location of interest within Minnesota.
That's it! Now you are viewing the different watershed boundaries for your location. Here are what the different boundaries mean:
- Pink outline: Local catchment that sends surface water to the point you selected.
- Light blue fill: All catchments upstream of your location.
- Surface water flows from this area into your catchment. This is your 'true' watershed.
- If the pink outline and light blue fill cover the same area, this is a 'headwater' catchment. Surface water flows out, but not into, the catchment.
- White outline: Major watershed boundary
- This boundary is used for managing resources and working with partners. It might be the upstream true watershed, or it might be an artificial subdivision of a larger watershed. This is your 'administrative' watershed.
- Dark blue fill: Catchments downstream of your location.
- Mask: Major river basin for the large river system connected to your location.
Because the first step for addressing any issue is to define the scope for your project or discussion. What is inside and what is outside? Where should I set the boundary for what I include? This is where scale comes in. Scale refers to the extent of something – how big, how far away, how many years.
Before selecting a boundary (size of area or length of time), you should think about what ‘process’ you hope to influence.
For watersheds, here are some key processes to consider:
- Sediment delivery: Where is sediment coming from? How big is the land area contributing surface water flow?
- Water flow and volume: Where is water coming from? How much of the connected river system is of concern?
- Contaminant sources: Where are the contaminants coming from? Are there sources/types that are of particular interest?
- Information delivery: What key audiences might need to alter their management of land and water resources? Where are the opportunities to work with communities and policy makers?
SELECTION PROCESS: With these questions in mind, review the nested watershed scales and decide which of these scales should be used to begin your investigation of watershed health:
- Catchment - smallest size watershed delineated in the WHAF
- watershed size ranges widely, but there are more than 10,000 catchments in Minnesota and the average size is about 6000 acres.
- may be appropriate scale to select, particularly for a ‘headwater’ catchment where all surface water originates within this boundary.
- Downstream - shows direction of surface water as it flows out of a catchment
- connects your location to the larger river system.
- downstream conditions might block flow with structures; impoundments and barriers influence water quality and movement of aquatic life.
- downstream contaminant sources and areas of expanding development may influence conditions upstream.
- Upstream -'true watershed' land area; contributes water and sediment to your selected catchment. If your location is on a major river, its upstream area may be very large. Consider conditions at this scale prior to deciding the appropriate watershed size for implementation.
- connects your location to its watershed landscape, review land use and land cover within this boundary.
- consider whether upstream conditions will overwhelm your potential action or approach.
- review the alteration of water storage and delivery systems, consider the upstream influence on flow volume and variability.
- Major Watershed - designated boundary for resource management, may be a ‘true watershed’ or may be an administrative boundary that sub-divides a larger 'true watershed'.
- for true watersheds, this scale is identifical to the upstream scale, with the same considerations for understanding sediment and water.
- much data collection, reporting and communication takes place at this scale which may influence project success.
- as an administrative boundary, this scale often connects the efforts of local government, state agencies and non-profit organizations.
- Major River Basin - this is the largest watershed delineated in the WHAF. This scale is important for comparing the conditions that may vary from one part of Minnesota to another, and can help with setting broad consistent priorities.
- consider this scale for implementing policy, or incentives
- communicating about concerns impacting large systems or all of Minnesota, will benefit from a summary of conditions at this scale
- view health score patterns and landscapes to look for conditions that vary or are consistent from one basin to another.
Other considerations may include:
- Legal jurisdictions related to zoning, land use incentives and land protection activities
- Boundaries – cities, townships, counties, states, tribal lands, easement holders
- Proximity to population centers as places that might benefit, have opinions, champion successes
- Boundaries – cities, towns, demographic groups
- Timeframe for a measureable response. This can vary dramatically, and may or may not match your project needs.
- Boundaries – funding cycle, report deadline, years, decades, centuries
Selecting the Major Watershed Boundary: Pine River Watershed
Your location is near the center of the Pine River Major Watershed. In this case, the major watershed boundary seems an appropriate scale to use for an exploration and evaluation of watershed health. Click to open this WHAF map.
Here are some reasons why:
- The major watershed is a 'true watershed'
- Sediment and water issues can be addressed at this scale.
- Most contaminant sources will fall within this boundary.
- The upstream area for your selected catchment includes the Pine River; but it is also hydrologically and biologically connected as a chain of lakes to the entire major watershed.
- There is an active effort to cooperatively manage the Pine River Major Watershed by both state agencies and citizens.
- The larger population centers are downstream of the selected location.
After investigating and collecting some insights at this scale, remember your next step is to check other scales:
- Zoom out to the Upper Missippi River Basin, look for conditions beyond the major watershed that may influence health and risk levels in this watershed,
- Zoom in to find local conditions that may directly impact the health of Whitefish Lake.
Upstream and Downstream Connections: Managing Mussels in the St. Croix River
Setting the boundaries to use when investigating the health of an aquatic community in a river system should include looking upstream and downstream of the site. In this example, a manager is exploring conditions that influence the mussel community near Folsum Island, in the middle of the St. Croix River.
Why Look Upstream and Downstream?
Mussel community health is directly tied to the presence of barriers to fish passage.
- Because their life cycle requires the presence of a specific host fish; if the host is blocked and not present, the mussel cannot reproduce.
Excessive sediment covering the streambed makes it difficult for sensitive mussel species to survive and thrive.
- Land use and land cover in the upstream contributing area will impact this aquatic community. In this case, some information in the WHAF Map does not extend beyond Minnesota. However, the land cover charts summarize national data, giving an important, accurate snapshot of the entire contributing area.