Ryan R. Morrison

Spatially implemented Bayesian network model to assess environmental impacts of water management

Bayesian networks (BNs) have become a popular method of assessing environmental impacts of water management. However, spatial attributes that influence ecological processes are rarely included in BN models. We demonstrate the benefits of combining two-dimensional hydrodynamic and BN modeling frameworks to explicitly incorporate the spatial variability within a system. The impacts of two diversion scenarios on riparian vegetation recruitment at the Gila River, New Mexico, USA, were evaluated using a coupled modeling framework. We focused on five individual sites in the Upper Gila basin. Our BN model incorporated key ecological drivers based on the “recruitment box” conceptual model, including the timing of seed availability, floodplain inundation, river recession rate, and groundwater depths. Results indicated that recruitment potential decreased by >20% at some locations within each study site, relative to existing conditions. The largest impacts occurring along dynamic fluvial landforms, such as side channels and sand bars. Reductions in recruitment potential varied depending on the diversion scenario. Our unique approach allowed us to evaluate recruitment consequences of water management scenarios at a fine spatial scale, which not only helped differentiate impacts at distinct channel locations but also was useful for informing stakeholders of possible ecological impacts. Our findings also demonstrate that minor changes to river flow may have large ecological implications.

A Classification Framework for Running Adaptive Management Rapids

While adaptive management (AM) is becoming a preferred natural resource management approach, the conditions necessary to engage in AM are not always present. In order for AM to work, there must be an ability to engage in experimentation and then incorporate what is learned. Just as few rivers are unequivocally either “runnable” or “unrunnable” by a whitewater boater, successful AM depends on a number of factors, including legal frameworks and requirements, resource allocation regimes and existing infrastructure. We provide a classification framework for assessing the physical and institutional capacity necessary for AM using the international classification for whitewater. We then apply this classification framework to the design of an AM program for New Mexico’s Rio Chama. As the case study illustrates, the classification system facilitates learning and provides an engaging way of thinking through problems and involving stakeholders. It can also help keep perceived limitations from becoming fixed reality, and it can be used to develop the conceptual model on which AM is based. The classification system allows practitioners to assess whether AM is possible by providing a way of thinking though the issues involved.

Hydrodynamics of Juvenile Salmon Passage in Sloped-Baffle Culverts

Recent evidence suggests that, although their ultimate destination is the sea, juvenile salmonids also travel upstream to locate more desirable habitat and feeding areas. Since many culverts are impassible to juvenile salmonids, baffle systems are being evaluated that will facilitate greater upstream passage. A culvert test bed facility at Washington Department of Fish and Wildlife Skookumchuck Rearing Facility near Tenino, Washington was built to test fish passage success and study the hydrodynamic regimes induced by the baffles. The study involved installing baffles within a 40 foot long, 6 foot diameter corrugated culvert and recording 3-D velocities using an Acoustic Doppler Velocimeter (ADV). The purpose of these tests is to describe the hydrodynamics of the baffle flow and to evaluate how different hydraulic conditions may benefit or hinder fish passage. Baffle generated flow structures such as a jet on the low side of the baffle or a roller wave are identified. Using the 3-D velocity data and surface images, the flow structures are then characterized according to their intensity and size. A scaling equation is analyzed to relate the modification of flow features to the independent study parameters. This paper establishes hydraulic guidance that can help biologists and engineers to improve baffle design and configuration to aid juvenile salmon migration.

Turbulence Observations in Cobble-Bed Rivers

Improving descriptions of natural stream flow fields is a critical step in restoring aquatic ecosystems. Current methods used for evaluating aquatic habitat rely on simplified representations of the flow field. These methods can be improved by incorporating important spatial and temporal flow field variations and more advanced habitat metrics. However, knowledge of velocity and turbulence distributions in natural streams is limited to laboratory derived empirical equations. Further, only limited experiments have been conducted in natural streams. The objectives of this research were to evaluate the adequacy of existing empirical relationships for describing natural stream flow fields and to investigate spatial distributions of flow variables. In this research, acoustic Doppler velocimeter (ADV) measurements were conducted at the reach scale (approximately 5 stream widths) in two cobble-bed streams. The measurements encompassed riffle, pool, and run stream units. The results showed that velocity distributions were adequately predicted with the log-law for all stream units and transverse locations. However, empirical turbulence intensity and turbulent kinetic energy equations inadequately described measured values. This was likely due to turbulence generation from stream banks, bedforms, obstructions, and other stream features.