Richard Horner

• University of Washington

Evaluate Washington's Water Quality Criteria Effectiveness

In this study, we developed the Urban Ecohydrology Model (UEM) to investigate the role of bioretention on watershed water balance, runoff production, and streamflow variability. UEM partitions the land surface into pervious, impervious, and bioretention cell fractions. Soil moisture and vegetation dynamics are simulated in pervious areas and bioret...

Measurement of chlorophyll a accrual on flattened rock substrates placed in streams revealed that a velocity increase up to ~50 cm∙s−1 enhanced periphytic algae accumulation when orthophosphate-phosphorus concentration exceeded 40–50 μg∙L−1. At lower P concentrations velocity increases reduced the accrual rate. The erosive effect of current was hyp...

Event-based, flow-paced composite sampling was carried out at the inlet and outlet of a street-side bioretention facility in Seattle, Washington, to assess its ability to reduce street runoff quantity and pollutants. Over 2.5 years, 48 to 74% of the incoming runoff was lost to infiltration and evaporation. Outlet pollutant concentrations were signi...

Research was performed in laboratory streams to evaluate periphytic biomass accrual, export, and community composition over a range of limiting nutrient (phosphorus) concentrations with variable velocity, and suspended sediment addition, in comparison to constant velocity and no suspended sediment. In fixed‐velocity treatments, velocity increase to...

Threatened Puget Sound chinook salmon and other imperiled anadromous and freshwater species continue to decline in Washington State due to the effects of diverse human actions. Recently, the Washington State Department of Ecology ("DOE") submitted revised water quality standards to the Environmental Protection Agency ("EPA") for federal approval. D...

Stream ecosystems in the Pacific Northwest (PNW) were found to benefit from the retention of native forest and wetland cover, as well as the minimization of impervious surfaces throughout the watershed. In addition, wide, continuous riparian buffers consisting of mature, native forest provided additional assurance of high aquatic ecosystem integrit...

Stream ecosystems in three different locations in the United States were found to benefit in a similar fashion from retention of watershed forest and wetland cover and wide, continuous riparian buffers with mature, native vegetation. The findings can help guide comprehensive watershed management and application of these non-structural practices in...

Various structural and non-structural best management practices (BMPs) have been proposed to mitigate the cumulative effects of urbanization, but little is known regarding the effectiveness of these BMPs in maintaining ecosystem integrity. This paper evaluates the effectiveness of the principal structural and non-structural BMPs used in the United...

1. These provisions currently have the status of guidelines rather than requirements. Application of these guidelines does not fulfill assessment and permitting requirements that may be associated with a project. It is, in general, necessary to follow the stipulations of the State Environmental Policy Act and to contact such agencies as the local p...

INTRODUCTION This chapter emphasizes water and soil quality in wetlands with significant urbanization in their watersheds. Like other chapters in this section, its purpose is to characterize particular elements of Puget Sound Basin freshwater wetlands having urbanized watersheds. The urbanized cases were divided into two major categories. The "trea...

Two wet detention ponds were investigated for their ability to remove pollutants, primarily phosphorus, from stormwater runoff. The two ponds lie within the Phantom Lake watershed, a sub-basin of the Lake Sammamish watershed in Bellevue, Washington, which is developed as a commercial and residential area with impervious surface area as high as 57%....

1. The proliferation of nuisance periphyton in enriched streams may be dependent on the biomass of the grazing macroinvertebrates present. In the present study, the effectiveness of grazer size and biomass in controlling periphyton and the extent to which grazing effectiveness was affected by enrichment level were determined. 2. Two sets of experim...

This paper summarizes the results of the Puget Sound Wetlands and Stormwater Management Research Program, which examined the impacts of urban stormwater on wetlands. Results are presented for data collected between 1988 and 1995 for 19 wetlands, showing changes in wetland hydrology resulting from urban conversion and the subsequent impacts on plant...

Grazing by the large caddisfly larva, Dicosmoecus gilvipes (Trichoptera; Limnephilidae), drastically reduced periphyton biomass in laboratory channels at a current velocity of 20 cm s–1. Reduction in biomass as chl a and AFDW ranged from 88 to 93% and 82 to 85%, respectively. On average, grazing rate increased with in-channel SRP (soluble reactive...

Comprehensive budgets of total suspended solids (TSS), total phosphorus (TP), total zinc (the most prevalent metal in urban runoff), and fecal coliforms (FC) were developed for two palustrine freshwater wetlands in Washington, USA. These budgets were based on input (inflow, precipitation, groundwater) and output (outflow, evaporation). One wetland...

Calcium magnesium acetate (CMA) was identified in the early 1980s as a material that is potentially effective for deicing highways, feasible to manufacture commercially, and environmentally acceptable. Its environmental acceptability required definitive testing prior to widespread application. This paper reports the results of comprehensive laborat...

Comprehensive laboratory and field experiments were performed to determine the potential effects of the experimental deicing agent calcium magnesium acetate (CMA) on aquatic and terrestrial ecosystems. A companion paper covers the overall results of these experiments. This paper concentrates on the leading concern to emerge from the testing, the po...

The identification, assessment and management of non-point source water pollution problems can be improved through better water quality monitoring program designs. The result is often more useful and reliable information for use by decision-makers. In this study of the Svart River Basin in south-central Sweden, the results of a modified monitoring...

Model predictions of periphyton biomass, as a function of ambient SRP concentration, were compared against observed biomass accrual on natural and artificial substrates in the Spokane River, Washington. A range in biomass was predicted based on uncertainties due to temperature, velocity, accumulation period and an empirical growth constant. Only 8...

This paper describes a computer-aided methodology designed to aid in the determination of water quality and ecological change resulting from nonpoint sources of water pollution. The nonpoint monitoring program design conceptual model developed by the writers involves the following steps: (1) The definition of monitoring program objectives to guide...

Relative coverage of filamentous periphytic algae increased with chlorophyll a (chl a) biomass on natural substrata in 22 northwestern United States and Swedish streams. A biomass range of 100–150 mg chl a m−2 may represent a critical level for an aesthetic nuisance; below those levels, filamentous coverage was less than 20%. Other indices of water...

Biologically available phosphorus (BAP) was determined monthly for a year in Lake Sammamish, Wash. and its principal inflow stream, to improve on previously developed relationships between TP from increased urban runoff and lake response (chlorophyll a and transparency). Relationships were developed between bioassay-determined BAP and a combination...

Cost-effective methods for obtaining data on water quality are reported. The focus is on three sampling program design issues that are essential to cost-effective hypothesis, testing and hence to the successful implementation of environmental monitoring programs. The three issues are determining the best strategy to sample the quantity of interest,...

Nutrient sources influencing eutrophication of Moses Lake, Wash., have been evaluated in a multistage investigation of urban and agricultural land uses in the watershed. Nutrient loadings from surface and groundwater contributions were quantified in a year-long monitoring program. Subsequent studies have assessed effectiveness of various control te...

A seasonal phosphorus model was used to predict the effect of proposed watershed development on water quality in Lake Sammamish, Wash. The model was calibrated and verified using daily loadings from two separate annual data sets. Phosphorus yields were scaled from literature values using actual loadings. Results indicate that substantial runoff con...

The recovery of Lake Sammamish from wastewater diversion in 1968 was delayed 7 years because sediment phosphorus release remained high until the mid-1970s. Marked reductions in phosphorus and chlorophyll a concentrations and an increase in transparency had occurred by the late 1970s. A general decline in sediment phosphorus release rate in the late...

In many complex environmental assessment tasks, the utilization of expert opinion is necessary when quantitative information is inadequate and when the cost of obtaining new knowledge is too high or requires too much time. The consensus of a panel of experts on a number of critical issues relating to the design of environmental monitoring programs...

The effectiveness with which a panel of experts, operating within the context of a Delphi technique, could be used to develop information for use in environmental monitoring program design and environmental decision-making was investigated. The Delphi technique was evaluated to determine selection criteria for an expert panel, how many panelists ar...

A protocol has been developed for assessing the impacts of highway operations and maintenance and determining the need for impact mitigation measures. By using an initial screening process a determination can be made as to whether or not a case is likely to have an insignificant impact. Substantial resources are expended on assessing only those cas...

A 5-year effort to characterize highway runoff in Washington State resulted in the accumulation of data from more than 500 storms at nine locations and the development of a guide for assessing aquatic impacts of operating highways. The data were used to construct a simple model that expresses cumulative pollutant loadings as functions of highway se...

Accrual of periphyton biomass in artificial channels responded more to increased SRP (soluble reactive phosphorus) concentration over a range of 2 to 75 µg l−1 than to velocity ranging from 5 to 75 cm s−1. Accrual increased in proportion to increased SRP up to about 25 µg l−1; but further increase was not as pronounced above that concentration, pre...

A stormwater runoff pollutant loading model has been developed on the basis of results from composite sampling of approximately 500 storms at nine locations in Washington State. One component of the model is an expression for total suspended solids (TSS) load in relation to traffic, runoff coefficient, and surrounding land use contributions. Other...

A stormwater runoff pollutant loading model has been developed on the basis of results from composite sampling of approximately 500 storms at nine locations in Washington State. The model as presently constructed is capable of predicting loadings over a time span encompassing a number of storms (monthly or annually), but has little precision when a...

A five-year study was performed to compare conditions in the Pilchuck River before and after channel reconstruction associated with rerouting highway SR-2. The study focused on sediment particle-size analyses, benthic macroinvertebrates and fish. Substrates comparable to control areas developed in all portions of the new channel within one year aft...

The lowland salmon spawning and rearing streams in the Puget Sound region (U. S. A.) and their watersheds were studied to identify the linkages between watershed conditions, specifically urbanization, and the habitat elements and biological responses. The study's intent was to produce a knowledge base for managing land with reference to ecological...

This volume discusses the implementation of the Delphi method and lists the data generated. The timetable of operation, the membership of the panel, all letters and questionnaires, and all responses are recorded, as well as a description of and the results of the analysis of the data. The purpose of this volume is to archive the information gathere...

With this methodology, utility personnel can combine site data and information on plant operating conditions to predict the potential effects of power generation on aquatic ecosystems and develop programs to test for their occurrence. Trade-offs between sampling costs and the value of information to be gained are used to select a cost-effective, st...

The Clean Water Act NPDES permit that regulates municipal separate storm sewer systems (MS4s) in Ventura County, California will be reissued in 2007. The draft permit includes provisions for requiring the use of low impact development practices (LID) for certain kinds of development and redevelopment projects. Using six representative development p...

The impacts of stormwater runoff from Washington State freeways on aquatic ecosystems were investigated through a series of bioassays utilizing algae, zooplankton, and fish. Algae and zooplankton were adversely suspended by the soluble fraction of the runoff, while suspended solids caused high mortalities of rainbow trout fry. In addition, BOD5 val...

Richard Horner will describe the elements of Pacific Northwest forest hydrology: trees and soils. He will contrast this to urban hydrology, where the hydrologic services of trees and soils are lost. He will describe the impacts of urban hydrology on streams and aquatic life. Solutions will be presented to alleviate urban impacts. Finally, Horner wi...