LiDAR, Fish Passage Barriers, and Riparian Mapping Feasibility Study
Wildlife & Ecosystems
Research Idea Scope
Fish passage barriers are a significant threat to the recovery of threatened and endangered fish and other aquatic species. There are often limitations to transportation funding that require the prioritization of barrier locations based on a variety of metrics. One such common metric is the length of stream anticipated to be available to various species after barrier removal. While it is often possible to visit a barrier spot location and measure detailed structural and habitat data, there are often limitations to gain access to areas upstream or downstream of the barrier location. LiDAR (light detection and ranging) has the potential to provide information that may directly influence barrier removal priorities. In addition, LiDAR may have the potential to provide information on unassessed road crossing locations or detect unknown barriers. Although there are few examples of this practice currently, the Wisconsin Department of Natural Resources has recently used LiDAR to survey road crossings and determine the elevation drop at each location down to the 0.5-foot level. This Transportation and Environmental Research Ideas proposal would assess the feasibility of using LiDAR to assess fish passage within streams, watersheds, and regions. The research would summarize the required technology (e.g. equipment specifications, point density) and survey conditions (e.g. time of year) to successfully map creek elevations and detect elevation drops <0.5 feet at road crossing locations. The research should investigate the cost and feasibility of fixed-wing and drone surveys, including potential partnerships to reduce costs. The research should investigate if other key stream metrics are possible to map reliably (e.g. thalweg, pool/riffle, riparian vegetation extent, canopy cover/height, etc.). A goal would be to maximize data collection per mapping survey. Research should also determine if data can be combined with existing methods, such as NOAA’s intrinsic potential and state fish passage barrier databases.
Urgency and Payoff
If LiDAR is feasible and cost-effective, DOTs and resource agencies can quickly and effectively map barriers and determine the potential upstream benefits of barrier removal. Fish passage improvements are costly, and LiDAR mapping may provide more confidence that unknown barriers do not exist directly upstream.
Andrew Amacher California Department of Fish and Wildlife 916-653-9779