Can the NHD Meet the Different Business Needs of Various Agencies in the Pacific Northwest?

1. Can the NHD Meet the Different Business Needs of Various Agencies in the Pacific Northwest? By Bill Kaiser, USFS April 15, 2009 NHD Stewardship Conference

2. Purpose of this Presentation: Examine the sometimes conflicting business needs of partner agencies and users of hydrograpy data in Oregon and Washington. Highlight how the NHD data was built and how, this in fact, caused some of the problems haunting us today. Explore the possibility that new technologies may help provide part of the solution to these disparite business needs.

3. Background From 1999 – 2003 the Pacific Norwest Hydrography Framework engaged partner in a collaborative effort to build the best available hydro data from the partner agencies. While jurisdictional, it was also hydrologically-based. A real Framework love fest – working wih best available data from agencies that knew about water and land!

4. Case 1 WA DNR contributed data over much of the private and state land. In general, these data are at a far greater density than most of the other partner data.

5. Differences in stream density within the PNW, Derby Creek, 6th Field watershed in Eastern Washington WA DNR hydro is more dense, Forest Service is less dense

6. DNR has a requirement to manage forest practices on state and private land. The model they use to predict periodicity, e.g. perennial, consistently under predicts the the number of perennial streams. DNR has requested that the Hydro framework adopt their density throughout the state of Washington. Legitimate business need. The Forest Service provides different levels of protection based upon whether a stream is fish- bearing, perennial, or intermittent based upon the Pacific Northwest Forest Plan. The language in the plan can interpreted as equating ephemeral streams with intermittent streams where there is evidence of deposition and scouring. Legitimate business need.

7. How to we reconcile these two representations? Use of ephemeral to attribute periodicity? Generalization tool? Get everybody to agree on field based regression equations? Science to the rescue!

8. Case 2 Researchers and modelers both regional ecosystem modelers (who ensure the Forest Plan is monitored) and Intrinsic Potential (IP) modelers who look for areas to restore possible salmon habitat have both expressed to PNW Hydro Framework that the NHD does not meet their needs mainly because of the inconsistent stream densities. This is raster-based analysis. Resource professionals expressed the requirement that there had to be a link between the IP model and the observed data that is on the NHD.

9. Case 2 continued…. Many researchers use a third party application called NetMap from Earth Systems Institute. It is the position of the PNW Hydro Framework that a DEM-derived hydro should be seen a temporary solution until NHD stream densities can be more uniform. The resolution of either case is, potentially, in conflict with the other one.

10. NetMap is raster-based and uses geomorphic techniques to determine such characterestics as gradient and valley floor width. It also accumulates attributes in the manner of ArcHydro.

11. Stream derived data from LiDAR may offer common ground if all parties can agree to a set of guidelines. Many pitfalls remain both technologically and institutionally. Agencies would have to make compromises and the technical solution is not easy. Sound science, data, and procedures need to published and adopted. When is a stream a stream? Use of minimum flow v. annual flow v. maximum flow…..