Interagency Hydrology Committee for Alaska (IHCA)

The Water Cycle

Date Last Modified: 13 JAN 2023

Current News

    Spring 2023 IHCA meeting: 9 and 10 March (IN PERSON with a virtual option)
               Location to be determined in Anchorage, AK 

             Agenda link will be available in Feb


    Fall  2022 meeting

    Recent meeting notes folder

Links to Alaskan Hydrologic Data

United States Geologic Survey:

State of Alaska:

State of Alaska Department of Conservation:

State of Alaska Department of Natural Resources:

National Weather Service:

US Fish and Wildlife Service


Chair, Ryan Toohey, United States Geologic Survey (USGS)

Vice-Chair, Ronald Daanen, Alaska Department of Natural Resources                    (AKDNR)

Secretary, Rosie Duncan, US Army Corps of Engineers

Past-chair, Kevin Petrone, Alaska Department of Natural Resources                    (AKDNR)

About Us

The Interagency Hydrology Committee for Alaska (IHCA) is an organization of technical specialists working at the Federal, State, and local levels, who coordinate the collection and implementation of water resources related data throughout the State of Alaska. The IHCA meets twice per year to coordinate multi-agency issues and exchange of information. 


Recent Water Resources Highlights

Announcement: AWRA-AK Section meeting scheduled for February 25-27, 2019, in Juneau (posted 8/27/2018)

Alaska Interagency Water Rights Course No. 1730-26 : October 24-28, 2016 (updated 3/30/2018)

Alaska NHDPlus Alpha, download data (posted 11/1/2017)

Alaska Hydrography Database (AK Hydro) (posted 10/1/2017)

NGWA Letter to President-elect Trump (posted 12/1/2016)

NOAA Water Initiative (posted 12/1/2016)

USGS Water Use Data Visualization Tool (posted 12/1/2016)


Coordinated efforts to address hydrological and climatological issues in Alaska dates back to the early 1960's when a "Technical Committee" was established under the auspices of the Subcommittee on Hydrology, Interagency Committee on Water Resources (ICWR). The parent committee became the Hydrology Committee of the United States Water Resources Council (WRC).

In 1977 members of the Interagency Technical Committee for Alaska developed an Organization, Objectives, and Operation statement in response to a growing need to improve coordination among agencies for hydrologic and climatologic data. In November, 1977 the Committee approved this document and adopted the name "Interagency Hydrology Committee for Alaska" (IHCA). The IHCA continued to operate under the sponsorship of, and receive guidance from, and report to the WRC Hydrology Committee.

Additionally, the IHCA has acted as the technical advisory committee of the past Governor's Alaska Water Management Council.