The New Fork River is the uppermost major tributary of the Green River.  The Gas Wells project reach is located on BLM land approximately 8 miles downstream of Boulder, WY. IMA was contracted by Trout Unlimited to produce a habitat assessment, hydrologic report, and habitat improvement design for the entire 1.5 mile reach.  In addition, the contract includes survey and design work for developing a boat access and parking area.  This section of the New Fork is characterized by widespread bank erosion, very little in-stream cover, poor pool development, high width to depth ratios, and insufficient sediment transport capacity.  Field data collection included pebble counts, detailed cross sections, a full longitudinal profile, flow measurements, in stream habitat evaluation, riparian vegetation evaluation, bank erosion hazard index measurements, and various Rosgen stream stability indices assessments.  The BANCS model was employed to rank eroding streambanks and prescribe appropriate stabilization measures.  The conceptual design focuses on stabilizing eroding banks, re-establishing woody vegetation, increasing pool to pool spacing, and reducing channel widths to promote sediment transport.

Concept design

Concept design

Erosion predictions from the BANCS model

Erosion predictions from the BANCS model

Eroding bank at the boatramp

Eroding bank at the boatramp

Surveying one of the deeper pools

Surveying one of the deeper pools