The Amended and Restated Upper Colorado River Wild and Scenic Stakeholder Group (SG) Management Plan (A&R SG Plan) was officially adopted in June 2020 and lists Channel Maintenance Flows (CMF) as a Resource Guide related to the Recreational Fishing Outstandingly Remarkable Value (ORV). The A&R SG Plan states that “CMF are important for maintaining a healthy aquatic and riparian and ecosystem that, in turn, supports a healthy recreational fishery and fishing experience. The SG has developed an Observational Monitoring Plan to better understand the effects that peak flows have on channel maintenance processes in Segments 4 through 6”. The CMF monitoring plan has been included in the Long-Term Monitoring Plan and is to be implemented as soon as practical.
The SG has agreed that the purpose of the CMF monitoring plan is not to identify a target flow, or range of flows for CMF, but to monitor the effects that a given year’s peak flows have on accomplishing general channel maintenance functions of mobilizing and transporting bed load substrate and channel maintenance processes of:
1. Maintaining amount and diversity of aquatic habitat.
2. Maintaining active channel geometry.
3. The creation and maintenance of non-vegetated sand and gravel features.
4. Preventing growth of new rooted vegetation and/or scouring rooted plants from active channel.
This RFP is only for cross-sectional channel surveys and sediment monitoring however, all of the following methods will be used to monitor CMF processes:
1. Cross-Sectional Channel Surveys: Systematic survey of cross-section topography that can capture riffle, run, and pool features. It is also used to monitor vegetation encroachment.
2. Substrate Measures (Pebble counts, % course/fine, algae, embeddedness): These methods enable better understanding of channel changes and includes:
a. Geomorphic measures to identify grain size distribution and median bed particle size,
b. Presence/absence of macrophyte coverage to provide an indication of potential movement,
c. Quantification of the percentage of fine sediments on the surface of a habitat feature such as a riffle or pool tail using a grid frame and,
d. Embeddedness data is also collected at each site to measure the depth of finer substrate surrounding the rock.
3. Drone-Based Aerial Imagery/Photogrammetry: Imagery (RGB) and LIDAR topography of current conditions (i.e., 2023). The information will characterize channel topography from (excluding areas beneath water surface), bank vegetation, and the nature of the channel morphology in the selected monitoring areas. Lidar data collected by the State of Colorado could be used to complement the Drone-Based Aerial Imagery/Photogrammetry analysis.
4. General Observer Notes: Includes general observations of geomorphology, substrate, riparian vegetation, and aquatic health characterizations (e.g., large fish pools). This method provides general awareness of channel condition.
5. Repeated Photo Points: Capturing photos at the same location over time to provide additional information and documentation related to changes in geomorphology, substrate, riparian vegetation, and aquatic habitat characterizations. This can be done periodically or automatically during a season or during an event.
Through this RFP, the SG is seeking qualified firms to conduct cross-sectional channel surveys and sediment sampling, as described in the Scope of Work Section below. The successful firm will be very familiar with and have experience in conducting cross-sectional surveys and sediment sampling in mountain river environments, specifically for the purpose of analyzing geomorphic conditions.
Statewide