Alaska Geospatial Council (AGC)

Alaska Hydrography Technical Working Group

Polychrome Pass image

Polchrome Pass in Denali National Park, Alaska. This environment, like much of the Alaskan landscape, is defined by water.

Alaska is an expansive state with abundant water resources. Its rugged and complex landscape is defined by water and ice. Despite these abundant water resources, Alaska lacks quality statewide surface water mapping, also known as hydrography.

While consistently mapped at a scale of 1:24,000 or better in the contiguous U.S, the National Hydrography Dataset (NHD) in Alaska was derived from 1950's era USGS Historical Topographic Maps at 1:63,360-scale. The NHD, the national dataset depicting the nation's surface waters, has seen limited improvements or enhancements in Alaska since its completion in 2008. It contains many errors including streams mapped outside their actual channels, misrepresentations of flowlines, disconnected streams and omission of existing streams.

Today, many Alaskans are now mapping Alaska's water and working to bring it in line with modern standards. By the end of 2017 nearly 20% of Alaska's hydrography will meet national 1:24,000-scale mapping standards. Although a lot of work remains to complete hydrography updates statewide, many partners are making great strides in improving this important dataset for all Alaskans.

AK Hydrography Status image

Since 2010 Alaskans have completed hydrography updates throughout the state. However, most of the state still needs to be updated to meet national mapping standards.

To date, more than 12,000 named streams and rivers stretching more than 850,000 miles, over one million lakes and more than 600 named glaciers have been mapped. Alaska's mapped coastline measures more than 47,000 miles long. And the state's longest river, the Yukon, is the third longest river in the U.S. measuring nearly 2,000 miles from its headwaters in Canada to its massive delta that empties into the Bering Sea.

Coordinating NHD Updates in Alaska

Skilak waterflow image

Selawik Lake and the Kenai River, Kenai Peninsula, AK. Hydrography editors utilize high resolution imagery and elevation data to better map the streams, rivers and lakes of Alaska. This improved data has innumerable applications throughout the state.

Many of the state's hydrography mapping issues stem from a lack of statewide mapping coordination in the past. Editors from different groups were scattered throughout the state. Each was working to fulfill their agency's needs, but not necessarily working towards statewide hydrography updates. These past practices resulted in the creation and use of numerous local hydrography datasets over the years.

In 2010 an effort in southeast Alaska brought together federal (USFS, USGS), state (AKDF&G) and academic (UAS) entities to update the NHD for the benefit of all hydrography users in the region. The collaborative stewardship model was successful. In 2012 it expanded into southcentral Alaska and became the Alaska Hydrography Database (AK Hydro). In 2013, recognizing the need for statewide surface water mapping coordination, many of the same federal and state entities, along with others, came together and formed the Alaska Hydrography Technical Working Group (AHTWG).

AHTWG remains an active group that addresses surface water mapping needs and issues in the state and coordinates NHD updates. The group now includes representatives from federal, state, local, academic, non-profit and industry entities. AHTWG successfully adopted AK Hydro as the stewardship model to coordinate, improve and move updated hydrography from partners into the NHD.

AK Hydro serves Alaska through two goals: first, updating the NHD in Alaska to national high-resolution standards and second, meeting the needs of Alaska's agencies. Utilizing AK Hydro ensures that updates happening throughout the state make their way into the NHD in a timely and consistent manner. And the stewardship model allows partners throughout the state to include important and necessary attributes with their hydrography datasets. Learn more about AK Hydro.

In order to complete statewide hydrography updates and meet the needs of Alaska, AHTWG and AK Hydro produced the Alaska Hydrography Strategic Plan. The strategic plan will promote and guide the core mission to efficiently serve the current and future hydrography needs of Alaska for the next 5 years (2017-2021).

Alaska Hydrography Strategic PlanPDF document 2029 Kb
Hydrography Technical Working Group CharterPDF document 160 Kb