Abstract: Session H 1:30 pm (Back to Session H)
Evaluating Design Decisions based on Monitoring at Meadowbrook Park
KCI Technologies, Inc.
Authors: Lucas, Shannon; Robert Owen
Stream restoration designers need to make a number of design decisions when preparing a restoration design. Due to limitations of time and budget, the decisions are typically based on a combination of site-specific measured data and non-site-specific data derived from regional relationships, reference sites, engineering norms, and modeled results. Additionally, regulations or guidance often prescribe methods or thresholds for various design parameters. Are these design decisions and thresholds overly conservative or are they cost effective approaches to attaining channel stability over a range of flows?
Since construction in the winter of 2011 to 2012, annual monitoring at Meadowbrook Park Stream Restoration in Howard County, Maryland includes surveying longitudinal profile, monumented cross sections, and riparian corridor. Monitoring at Meadowbrook Park also includes continuous stormflow sampling and bedload transport (buckets embedded in the streambed). Monitoring results document the post-construction condition; evaluate nutrient and sediment load reductions, and the physical stability of the channel.
This presentation uses the monitoring data to assess the various assumptions and decisions made during the design phase to determine if they are sound or if there are lessons to learn. Design parameters assessed include: design discharge estimates compared to the flow duration curves developed from the nearby stormflow gage; the design cross section compared to the storm flow-adjusted post-construction cross section; the specified riffle grade control material size and bed material mix compared to the largest particles and gradation of the measured bedload samples; the stability of specified bank materials and treatments; and riparian buffer health.