The DSSAM Model (Dynamic Stream Simulation and Assessment Model) is a

computer simulation Computer simulation is the process of mathematical modelling, performed on a computer, which is designed to predict the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be dete ...

developed for the

Truckee River The Truckee River is a river in the U.S. states of California and Nevada. The river flows northeasterly and is long.U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map accessed October 20, 2012 The ...

to analyze

water quality Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...

impacts from

land use Land use involves the management and modification of natural environment or wilderness into built environment such as settlements and semi-natural habitats such as arable fields, pastures, and managed woods. Land use by humans has a long h ...

and

wastewater Wastewater is water generated after the use of freshwater, raw water, drinking water or saline water in a variety of deliberate applications or processes. Another definition of wastewater is "Used water from any combination of domestic, industr ...

management decisions in the Truckee River Basin. This area includes the cities of

Reno Reno ( ) is a city in the northwest section of the U.S. state of Nevada, along the Nevada-California border, about north from Lake Tahoe, known as "The Biggest Little City in the World". Known for its casino and tourism industry, Reno is the c ...

and

Sparks, Nevada Sparks is a city in Washoe County, Nevada, United States. It was founded in 1904, incorporated on March 15, 1905, and is located just east of Reno. The 2020 U.S. Census counted 108,445 residents in the city. It is the fifth most populous city in ...

as well as the

Lake Tahoe Lake Tahoe (; was, Dáʔaw, meaning "the lake") is a Fresh water, freshwater lake in the Sierra Nevada (U.S.), Sierra Nevada of the United States. Lying at , it straddles the state line between California and Nevada, west of Carson City, Nevad ...

Basin. The model is historically and alternatively called the ''Earth Metrics Truckee River Model''. Since original development in 1984-1986 under contract to the

U.S. Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it be ...

(EPA), the model has been refined and successive versions have been dubbed DSSAM II and DSSAM III. This

hydrology transport model An hydrological transport model is a mathematical model used to simulate the flow of rivers, streams, groundwater movement or drainage front displacement, and calculate water quality parameters. These models generally came into use in the 1960s a ...

is based upon a pollutant loading metric called ''

Total maximum daily load A total maximum daily load (TMDL) is a regulatory term in the U.S. Clean Water Act, describing a plan for restoring impaired waters that identifies the maximum amount of a pollutant that a body of water can receive while still meeting water quali ...

(TMDL).'' The success of this flagship model contributed to the Agency's broadened commitment to the use of the underlying TMDL protocol in its national policy for management of most river systems in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. The Truckee River has a length of over and drains an area of approximately 3120 square miles, not counting the extent of its

sub-basin. The DSSAM model establishes numerous stations along the entire river extent as well as a considerable number of monitoring points inside the

Great Basin The Great Basin is the largest area of contiguous endorheic basin, endorheic watersheds, those with no outlets, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja California ...

's Pyramid Lake, the receiving waters of this closed hydrological system. Although the region is sparsely populated, it is important because Lake Tahoe is visited by 20 million persons per annum and Truckee River water quality affects at least two endangered species: the

Cui-ui The cui-ui (''Chasmistes cujus'') is a large sucker fish endemic to Pyramid Lake and, prior to its desiccation in the 20th century, Winnemucca Lake in northwestern Nevada. It feeds primarily on zooplankton and possibly on nanoplankton (such as a ...

sucker fish and the

Lahontan cutthroat trout Lahontan cutthroat trout (''Oncorhynchus clarkii henshawi'') is the largest subspecies of cutthroat trout, and the state fish of Nevada. It is one of three subspecies of cutthroat trout that are listed as federally threatened. Natural history ...

Development history

Impetus to derive a quantitative prediction model arose from a trend of historically decreasing river flow rates coupled with jurisdictional and tribal conflicts over water rights as well as concern for river biota. When expansion of the Reno-Sparks Wastewater Treatment Plant was proposed, the EPA decided to fund a large scale research effort to create simulation software and a parallel program to collect field data in the Truckee River and Pyramid Lake. For river stations water quality measurements were made in the

benthic zone The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning " ...

as well as the topic zone; in the case of Pyramid Lake boats were used to collect grab samples at varying depths and locations. Earth Metrics conducted the software development for the first generation

computer model Computer simulation is the process of mathematical modelling, performed on a computer, which is designed to predict the behaviour of, or the outcome of, a real-world or physical system. The reliability of some mathematical models can be deter ...

and collected field data on water quality and flow rates in the Truckee River. After model calibration, runs were made to evaluate impacts of alternative land use controls and discharge parameters for treated

effluent Effluent is wastewater from sewers or industrial outfalls that flows directly into surface waters either untreated or after being treated at a facility. The term has slightly different meanings in certain contexts, and may contain various pollut ...

. The DSSAM Model is constructed to allow dynamic decay of most pollutants; for example, total nitrogen and phosphorus are allowed to be consumed by benthic

alga Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular mi ...

e in each time step, and the algal communities are given a separate population dynamic in each river reach (e.g.metabolic rate based upon river temperature). Sources throughout the watershed include non-point agricultural and urban stormwater as well as a multiplicity of point source discharges of treated municipal wastewater effluent. Subsequent to the first generation of DSSAM model development, calibration and application, later refinements were made. These augmentations to model functionality focussed on increased flexibility in modeling the

diel Diel vertical migration (DVM), also known as diurnal vertical migration, is a pattern of movement used by some organisms, such as copepods, living in the ocean and in lakes. The word ''diel'' comes from the Latin ''dies'' day, and means a 24-h ...

cycle and also allowed inclusion of analyzing particulate nitrogen and phosphorus. In developing DSSAM III several changes in the model operation and scope were performed.Brock, J.T., C.L. Caupp, and H.M. Runke, '' Evaluation of water quality using DSSAM III under various conditions of nutrient loadings from municipal wastewater and agricultural sources: Truckee River, Nevada''.. Bureau of Water Quality Planning, Nevada Division of Environmental Protection, Carson City, Nevada (1992)

Applications

Numerous different uses of the model have been made including (a)analysis of public policies for urban

stormwater Stormwater, also spelled storm water, is water that originates from precipitation (storm), including heavy rain and meltwater from hail and snow. Stormwater can soak into the soil ( infiltrate) and become groundwater, be stored on depressed la ...

runoff, (b) researching agricultural methods for

surface runoff Surface runoff (also known as overland flow) is the flow of water occurring on the ground surface when excess rainwater, stormwater, meltwater, or other sources, can no longer sufficiently rapidly infiltrate in the soil. This can occur when th ...

minimization, (c) innovative solutions for non-point source control and d)engineering aspects of treated wastewater discharge. Regarding stormwater runoff in Washoe County, the specific elements within a new

xeriscape Xeriscaping is the process of landscaping, or gardening, that reduces or eliminates the need for irrigation. It is promoted in regions that do not have accessible, plentiful, or reliable supplies of fresh water and has gained acceptance in other ...

ordinance were analyzed for efficacy using the model. For the varied agricultural uses in the watershed, the model was run to understand the principal sources of adverse impact, and management practices were developed to reduce in river pollution. Use of the model has specifically been conducted to analyze survival of two

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

found in the

and Pyramid Lake: the

sucker fish (endangered 1967) and the

(threatened 1970). When the model is used for

reaching a stream, this pollutant input can be viewed as a

line source A line source, as opposed to a point source, area source, or volume source, is a source of air, noise, water contamination or electromagnetic radiation that emanates from a linear (one-dimensional) geometry. The most prominent linear sources a ...

(e.g., a continuous linear source of pollution entering the waterway).

References

{{reflist

External links

U.S. Environmental Protection Agency TMDL program for the Truckee RiverFinal TMDL waste loads for the Truckee Basin derived from the DSSAM Model
Computer-aided engineering software United States Environmental Protection Agency Hydrology Water pollution

Development history

Applications

See also

References

External links