Integrated Water Resources Management Act of 2005

Integrated Water Resources Management Act of 2005 - Directs the Secretary of the Army to include as a primary mission of the Army Corps of Engineers the provision of technical services and assistance to support planning, conservation, and responsible integrated management of water resources by State, tribal, interstate water resources organizations, and local governments.

Amends the Water Resources Development Act (WRDA) of 1974 to authorize: (1) the Secretary, at the request of a governmental agency or non-Federal interest, to provide technical assistance in managing water resources; and (2) the non-Federal contribution for preparation of a plan subject to the cost-sharing program to be made by the provision of services, materials, supplies, or other in-kind services.

Amends the WRDA of 1986 to set the non-Federal share of the costs of a watershed and river basin assessment on or after December 11, 2000, at 25 percent. Authorizes the Secretary to allow a non-Federal interest credit toward its share of the costs for certain projects or studies. Directs the Secretary to undertake: (1) measures to more effectively meet the current water resources needs of the areas impacted by Corps reservoirs; and (2) a program to provide public access to water resources and related water quality data.

Modifies provisions under the Flood Control Act of 1970 and the WRDA of 1986 regarding partnership agreements for water resources projects. Directs the Secretary to establish a program to provide environmental assistance to non-Federal interests in Texas.