Watershed Management Planning and Design

At Pacific Water Resources, Inc. (PWR), we are committed to understanding and enhancing the whole world of water, which goes far beyond a traditional "hard" engineering approach to encompass values of water quality, watershed health, and an understanding for the behavior of a stream system as a whole. We call ourselves water resources engineers, but we are experts in the fields of hydraulics, hydrology, water quality, geomorphology and computer aided mapping. This experience is evident in our ability to analyze, plan, design and implement cost-effective, practical solutions for our clients.

An excellent example of these unique capabilities is in the area of watershed management planning. Over the past twenty five years, PWR's staff has developed comprehensive watershed management plans for the Oregon cities of Durham, Eugene, Lake Oswego, La Grande, Oregon City, Tigard and West Linn; portions of Beaverton, Gresham, Milwaukie, Portland, Salem, Springfield, Clackamas County, Lane County, Marion County, Multnomah County, Washington County and four southwestern Counties in the state of Washington. The development of these various plans required the detailed hydrologic modeling of over 1,300 square miles with a combined total of over 4,000 subbasin areas and hydraulic modeling or evaluations of approximately 1,000 miles of urban, ubanizing or natural streams.

The importance of judicious use of our water resources grows greater every day. The Federal Water Pollution Control Act Amendments of 1972 grew out of a growing public awareness and concern for the quality of our nation's water. In 1977 additional amendments, which became known as the Clean Water Act (CWA), gave the EPA authority to control discharges to public waters. It also required the EPA to set water quality requirements for all contaminants in all of the nation's surface waters. These water quality requirements have been promulgated through regulatory programs identified by acronyms like NPDES, UIC and TMDL that PWR staff has considerable experience in helping our clients understand and implement.

Twenty-two years later in 1999 the National Marine Fisheries Service (NMFS, now NOAA Fisheries) listed nine new subspecies of salmon and steelhead as endangered in accordance with the Endangered Species Act (ESA). This was the first time listings affected major metropolitan areas and construction of roads and houses, agricultural practices and energy production.

Salmon in the Pacific Northwest are icons of our unique environmental quality. Settlers arriving here 150 years ago found abundant fisheries and other aquatic resources. Today over 9 million residents of Oregon and Washington occupy the same space shared relatively recently by so few. This influx of humanity and its associated infrastructure has led to environmental impacts which we are only now beginning to understand.

At the time of the listings the best available science indicated that human alterations to the landscape were causing a decline in the productive capacity of our streams. In the Columbia Basin alone, more than 50 species of salmon and steelhead are known to be extinct. As we move forward from now the question becomes how soon can we make a difference?

As cities become more urbanized and additional species are placed on threatened and endangered species lists, the careful management of precious watershed resources becomes essential to our quality of life. At Pacific Water Resources we believe that proper planning, good science and wise management can reduce flooding, improve water quality, enhance wildlife habitat and greatly contribute to watershed stability and health.

Pacific Water Resources staff has been known for some twenty five years as urban watershed master planners. Our technical expertise has been at the forefront of every major regulatory and technical advancement for assessing, enhancing and protecting water resources since 1978. Today we are still recognized leaders and innovators in watershed management planning and design.

 

 
Hydrologic / Hydraulic Modeling

Models are tools to help us understand physical phenomena. Their use is as much art as science because of the varied ways in which they are applied. At Pacific Water Resources we use hydrologic and hydraulic models for estimates of: storm flow frequency and magnitude, floodplain water surface elevations and mapping, historic flow events, low flow (i.e. bank full) events, storm pipe system deficiencies and capital improvements programs, sediment transport, scour and accretion, pollutant loadings and the benefits of various best management practices (BMPs), and direction and magnitude of forces in 2-D flow nets. We use models on a daily basis for evaluating complex hydrologic, hydraulic, sediment transport and water quality problems and to support design decisions for construction projects.

The number of commonly used models throughout the Pacific Northwest is proliferating. This is due in part to advancements in technology. The earliest computer applications were adaptations of hand calculation algorithms. The computational speed of these first computer applications allowed rapid development of new capabilities. Eventually, these were converted to the desktop computer environment and mainframe speed and computational ability became ubiquitous.

This process continues today with super computers in academia. Specialized hydraulics laboratories are developing new numerical analysis techniques which eventually will become specialized engineering applications. Hydrodynamic unsteady flow programs are now commonly in use and 2-D flow and sediment transport modeling applications are becoming more available. GIS capability or links are frequently incorporated for preparing input data. These tools enhance our ability to rapidly evaluate numerous alternatives and understand problems but their limitations must be understood as well.

At Pacific Water Resources we never forget that models are simply tools to help us understand complex phenomena. At their most basic levels lie a set of assumptions which must always be understood. For this reason, model results should, as much as possible, be tested by seasoned engineering judgment and verified by field observations.

The proliferation of models means that PWR must maintain a large number of highly specialized applications to meet our client's diverse needs. Only a firm specializing in hydrologic and hydraulic modeling can afford to be proficient at and maintain this number of models. Larger firms are usually proficient at one or two steady-state or hydrodynamic models. PWR maintains most models used regionally and possesses the necessary staff expertise and understanding for successful applications.

 
Fluvial Geomorphology Studies

Understanding bed mobility and channel stability are important concepts for problems involving infrastructure in rivers or stream restoration. Rivers and streams are in a state of dynamic equilibrium constantly moving and adjusting to the forces that shape them. The study of the forces that shape streams is fluvial geomorphology. This science is important because it links the hydraulics of flow to aquatic habitat.

Aquatic organisms adapted over hundreds of generations and thousands of years to their environments. Their environments over this period were shaped by patterns of disturbance brought about by flow, sediment transport and watershed cover. When any of these patterns are altered the results get "communicated" to the stream through these same paths.

Since Western European settlement of the Pacific Northwest human alterations of the landscape have accelerated the patterns of disturbance to which aquatic organisms adapted. Landscape changes from agriculture and urbanization have brought about increased erosion, altered natural vegetation communities and increased stormwater runoff. These changes as well as more direct interventions have altered aquatic environments faster than organisms can adapt.

PWR's goal is to work at the watershed level to address the factors causing stream and channel stability problems. If these can be controlled or mitigated then water quality and habitat will be improved leading to improved aquatic conditions over the long term. These are the goals of the Clean Water Act and the Endangered Species Act. We believe that by working with natural processes and understanding them, we can meet society's needs while at the same time restoring the quality and productivity of our waterways.

PWR's geomorphic work has included sediment balance studies, sediment load estimates, bank stability analysis, channel migration studies, and numerous scour and erosion studies at structures. Our staff has performed literally hundreds of bridge scour studies throughout the Pacific Northwest for clients including the State of Oregon and the Federal Highway Administration.

Habib Matin, Ph.D., one of PWR's founding principals, is a recognized expert in sediment transport modeling. Dr. Matin developed the first PC version of the HEC-6 model as part of his Master's Degree work at Oregon State University. He has also developed computer programs for several sediment transport equations. His Ph.D. thesis was based on a several years long detailed study and monitoring of sediment transport processes of gravel bedded rivers in the Pacific Northwest.

Sediment transport models like HEC-6, which is available from the US Army Corps of Engineers (USASCE) Hydrologic Engineering Center (HEC), can simulate the processes of deposition and scour in rivers and reservoirs. These types of models can analyze up to 15 different particle sizes (ranging from clay to large gravels) and has the ability to simulate armoring and the destruction of the armor layer, an important sediment transport process in gravel bedded rivers. PWR's expertise in the use of sediment transport models to evaluate complex fluvial geomorphologic problems results in practical and cost-effective stabilization solutions for our clients.

Water Quality Planning and Design

 On February 6, 2003 the Seattle Post-Intelligencer reported on a 'ground breaking' study conducted in the fall of 2002 by NOAA Fisheries, which suggested stormwater effects could kill fish. (Our Troubled Sound: Spawning Coho are dying early in restored creeks, Lisa Stiffler and Robert McClure) "The culprit appears to be stormwater gurgling off streets…when hit by a flush of it, Coho are immediately disoriented." The federal scientists who performed the research noted that 88 percent of fish in the study died within hours of exposure. This despite millions of dollars spent to restore Seattle area streams. NOAA Fisheries now advocates an increase in stormwater treatment levels and additional research is being conducted to determine the pollutant or pollutants responsible for the fish deaths.

Stormwater from urban development is very complex and highly variable. This makes the characterization of stormwater a daunting task. The accumulated data that describes stormwater quality indicates that concentrations and loadings vary widely within and between storms and within and between sites. Understanding this variability is central to decisions regarding stormwater treatment, the selection of a treatment process, its sizing, and whether to employ multiple treatment processes and their relative sizing and maintenance schedule.

Clearly the issue of the appropriate rainfall intensity and storm volume for stormwater treatment design needs to be addressed, especially in light of the NOAA Fisheries study mentioned earlier. It is quite possible that the fish kills reported by NOAA Fisheries may be related to elevated copper or pesticide concentrations occurring in stormwater during early fall storms when the accumulation of pollutants on the urban landscape is at its greatest. So there is also a need to understand the differences in rainfall characteristics between the late summer to early fall season verses the whole rainfall year.

Ultimately the final question that needs to be answered isn't just how large of a storm is receiving treatment, but how much of the pollutant mass is actually being removed or how effective is the treatment technology in reducing pollutant loadings and concentrations. The answer to this larger more important question requires a much better understanding of the water quality characteristics of urban runoff and how the physical characteristics of the upland urban landscape and the human activities on these landscapes, like the use of the automobile, affect these characteristics. The answer to this larger more important question also requires a much better understanding of treatment technologies and the potential pollutant removals associated with source control BMP's like street and catchbasin cleaning.

Understanding stormwater treatment begins with the knowledge of the runoff to be treated. PWR President Roger Sutherland began his studies of stormwater quality in 1973 as part of his master's research at the University of Maryland. Mr. Sutherland, along with other PWR staff, is experienced in the practical application of water quality computer models. He is the principal author of a state-of-the-art urban stormwater quality model call SIMPTM which has been used in numerous projects over a thirty year period.

SIMPTM is a continuous, self-contained stormwater quality model that can accurately simulate the accumulation, washoff, and BMP related removal of accumulated sediment and its associated pollutants including dissolved pollutants. The model simulates sediment and bound pollutant transport using the Yalin-Einstein and Foster-Meyer equations. This has been shown by Mr. Sutherland to be much more accurate than the empirically based exponential washoff used, for example, in EPA's Storm Water Management Model (SWMM).

SIMPTM also accounts for sediment deposition, armoring, and resuspension processes. Between events, SIMPTM calculates dry deposition and resuspension processes and models scheduled cleaning of streets, parking lots, catchbasins, or maintenance hatches. Overall removals from these practices are provided by SIMPTM based upon measurable data, rather than input by the user, as most stormwater quality models require. Any excess erosion remains available for further simulation, so that actual accumulations may often exceed the equilibrium load previously assumed by most other models to be a maximum limit to accumulation.

SIMPTM has been used extensively in the Portland, Oregon area as part of surface water management and water quality management plan development since 1988. It was used in 2001 for two similar projects conducted in Livonia, Michigan and Jackson, Michigan. SIMPTM has been used in the Seattle area several times and its predecessor in Anchorage, Alaska, Reno/Sparks, Nevada, and throughout urban Illinois. The United States Geological Survey (USGS) applied the model in the Dallas, Texas area in 1992 and concluded that it provided the most accurate simulation results when compared to several other models that were tested including SWMM. The model is currently being used for the evaluation of a highway in Tel Aviv, Israel.

Stream Stabilization, Restoration
and Enhancement Design

The requirements of the Clean Water Act (CWA) and the Endangered Species Act (ESA) are forcing a critical evaluation of human impacts on aquatic resources. The goals of improving water quality and habitat productivity require new approaches to development and construction. Similarly, the goal of habitat enhancement (also referred to a stream stabilization, rehabilitation, restoration and enhancement) requires new paradigms by agencies and engineers. From an engineering standpoint, habitat enhancement projects are challenging for a number of reasons. There are no widely accepted design standards or materials specifications. No systematic design methods or approaches are available in standard engineering handbooks. Design methods that are available tend to be prototypical, subject to change and of limited applicability.

Traditional engineering approaches are expensive and difficult to apply to these projects. Professional practice guidelines rely heavily on the 'standard of care' concept. This states that design professionals must render services "with the ordinary degree of skill and care that would be used by other reasonably competent practitioners of the same discipline under similar circumstances." This legal concept dates to English Common Law Doctrine and limits the engineer's ability to innovate.

Practice standards consider "contemporary state of the art and geographic idiosyncrasies." What does this mean in a completely new field of endeavor? Traditional river engineering approaches are now viewed as destructive to habitat. How can engineers innovate in the field of aquatic habitat enhancement when the standard of care is not yet defined? Previous experience shows that habitat enhancement projects are prohibitively expensive using traditional engineering services models. Are there alternatives to the traditional models of providing engineering services?

Pacific Water Resources, Inc. (PWR) provides assistance to public agencies in developing solutions to these problems. Until regionally accepted standards are available, stream restoration and enhancement projects will involve more risk than traditional endeavors. Fundamentally, this work involves natural systems, which are inherently unpredictable. The use of non-traditional design and construction methods impart additional risk. The current institutional framework holds the engineer liable if the constructed project fails to perform. For these reasons, practicing professionals who desire to innovate must develop new risk management techniques. PWR's approach to this dilemma is to team with our clients in the identification and sharing of the risk. Our role on many of the stream restoration and enhancement projects is to identify and quantify the risk of failure, which allows our clients the ability make informed decisions regarding project design and implementation.

While innovative design approaches are becoming more common, innovative construction approaches are relatively new. Building with organic materials such as large wood debris (LWD) or plantings is still largely experimental. Organic materials are not dimensionally or physically uniform. Nuances of localized hydraulic phenomena and geomorphic changes over time are not easily predicted. The traditional construction process involving plans and specifications, bidding and construction with casual observations by the engineer is not well suited to non-traditional materials. For these reasons, post project monitoring is absolutely essential for identifying potential problems and learning from past experiences.

PWR's mission is to be the first choice firm for stream restoration and enhancement based upon expertise, experience and the quality of our work. Our goal is to simply provide our clients with the most innovative and cost effective solutions to their stream stabilization, restoration and enhancement challenges.