Mapping A Community Rich In Aquatic Resources
Encompassing over 25,000 square miles, the Matanuska-Susitna (Mat-Su) basin is rich in aquatic resources and freshwater habitat upon which healthy wild salmon populations depend. The Mat-Su is also home to Alaska’s second largest and rapidly growing human population. The Nature Conservancy believes this vast watershed can be one of the first places where people and salmon can sustainably share habitat and thrive together.
To achieve this goal, a holistic, science-based understanding of the freshwater environment salmon require is crucial, including mapping and identifying the characteristics of the streams and lakes they use throughout their lifecycle.
In the fall of 2013, The Alaska Chapter of The Nature Conservancy initiated a hydrographic mapping and analysis program in the Mat-Su basin using newly available, high-resolution topographic data to map all lakes, rivers and streams to a level of quality and technical specification suitable for ingest into the 1;24,000 scales USGS National Hydrographic Dataset (NHD)
The flagship products from this work are geometric networks of hydrologic flow as well as a suite of secondary hydrographic datasets to support ecological classification, flood and habitat risk assessment, ecosystem service valuation and decision-support for balancing of conservation and resource development.
The Result: Thousands of New Streams
Completed in December of 2015, through this work over 27,000 miles of previously unmapped streams were discovered in the Mat-Su basin. That is, enough new streams were mapped to travel around the equator with a bit left over. Overall, a grand total of 52,718 miles of streams and over 20,000 lakes have been conflated to the USGS National Hydrographic Dataset. The new stream maps are being used by several agencies and local governments to address issues of water quality, development and zoning requirements as well as conservation planning and habitat studies.