1. Josh Jones & Alyssa Weatherford EGEO 451, Winter 2011

2. WHY? ArcHydro is used mainly by hydrologists or GIS professionals interested/working in the field of water resources. Even if you are not directly interested in water resources, it is at least beneficial to know some basic processes within a very powerful and extensive set of tools. Watershed analysis is used by many others because of how dependent humans and animals are on water. If a watershed becomes contaminated many problems can arise because of this watershed conservation is a big deal. This presentation outlines the necessary steps to develop stream network flow in regards to a Digital Elevation Model.

4. DEM : J:\GEO\GEO_data\WA_USGS\DEM_10_MOSAICS\Bham_Whatcom_Co\w_wc_dem Hydrology : USGS, National Hydrography Dataset, http://nhd.usgs.gov/

5. This step creates linear features between the raw DEM and the hydrography layer, which is needed to develop flow on the stream network.

7. Each pixel in the resulting DEM is assigned a direction of the path of steepest descent. Each number, although seemingly nonsensical values have been chosen, represents a direction. 1=E, 2=SE, 8=S, etc.

13. Drainage Lines, usually located on higher order streams or on high topography

16. Problems  Watershed delineation did not always reflect the watersheds in their true form. Lake Whatcom was showed draining out of a channel in the Northeast instead of through Whatcom Creek at first.  After trying numerous DEM’s and different stream networks, it did finally show the correct drainage path.  This type of analysis is very picky, when you think you barely changed something it ends up not doing the analysis correctly.

17. Whatcom Watershed  There are two groups of people, one who want to develop the watershed and other who want to make the Whatcom watershed DNR land.  The Whatcom watershed is the main drinking water source for over 95,000 people.  Development and allowing to log can lead to contamination of water and landslides due to the areas steep slopes and high rain fall.

18. DEMO By Josh Jones

19. QUESTIONS?

20. Sources: Vaddey Sesgu & Harman, Rhett. Basics of Arc Hydro: Building a New Foundation for Water Resources USGS Conservation Northwest. Next Step for a Whatcom watershed Preserve. November 9, 2009. http://www.conservationnw.org/oldgrowth/whatcom-county-council-approves-next-step- in-creating-the-lake-whatcom-forest-preserve. Retrieved Feburary 28, 2011 For more Whatcom Watershed Information About Our Drinking Water http://lakewhatcom.whatcomcounty.org/ http://www.ecy.wa.gov/biblio/99337.html About Development http://www.co.whatcom.wa.us/publicworks/water/lakewhatcom.jsp About Conservation http://www.conservationnw.org/oldgrowth/whatcom-county-council-approves-next-step-in- creating-the-lake-whatcom-forest-preserve http://www.lakewhatcom.whatcomcounty.org/asub_fldrs/about_us/program_areas/land_pres ervation.shtml