Hangman (Latah) Creek Watershed Planning Project

Habitat and Land Use

There are various factors leading to the non-compliance of water quality standards on Hangman Creek. Agriculture is the significant land use within the basin (64%). The largest agricultural production areas are located in the upper to middle reaches of the watershed. Most of the cropland is non-irrigated, annual small grain production. Other crops include peas, lentils, canola, and turfgrass seed. The development of agriculture in the watershed led to a significant reduction of riparian vegetation and extensive channel alterations. The removal of native riparian vegetative buffers has reduced the natural filtering function and increased the rate of stream bank erosion.

The watershed also has an undetermined quantity of livestock that have unrestricted access to small tributaries and the mainstem of Hangman Creek. Over the years, the removal of woody vegetation and continuous trampling by livestock has significantly degraded the riparian areas and stream banks. These issues contribute to temperature and dissolved oxygen violations that have been documented throughout the basin.

The basin has many small rural towns located on major tributaries and the mainstem of Hangman Creek. Several of these towns have wastewater treatment plants that discharge directly into a tributary or the mainstem of Hangman Creek. The flows during the summer are often inadequate for effluent inputs and may contribute to low dissolved oxygen levels and other water quality violations.

The lower reaches of the watershed are moderately urbanized, but future growth projections by the City of Spokane indicate that the Hangman basin will absorb approximately 50 percent of the city’s growth over the next 10 years (SRTC, 1997). There are currently two golf courses, with a third currently being developed, on Hangman Creek and its tributaries. The unconsolidated sediments in the lower watershed consist mainly of alluvium and flood deposits that are highly erodible. Past and current development in these areas has removed riparian vegetation and exacerbated the sediment and nutrient loading problems as the eroded soil runs into the waterways.

Fish habitat and distribution throughout the watershed has radically changed over the last one hundred years. Hangman Creek once had viable populations of native redband trout and healthy runs of salmon and steelhead. The removal of riparian vegetation, channel alterations, and heavy sedimentation has significantly reduced the spawning and rearing habitat on Hangman Creek. The primary species now found in the stream are adapted to warmer, slower waters and considered undesirable as gamefish. Resident trout populations are severely depressed.

It is not difficult to assess the future outcome for water resources issues in the Hangman Creek watershed if the current situation is not addressed. The lower watershed will be subjected to heavy urban development, some agricultural producers will continue to farm the edges of the creek, livestock will trample the banks and pollute the water, the creek will discharge hundreds of thousands of tons of sediment into the Spokane River, and fish habitat will dwindle until only warm water species thrive. In summary, most beneficial uses will continue to be impaired.

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