Development and Preliminary Application of Mathematical Models to the Weber Basin

The adoption of stream standards, whether for direct application or for the establishment of realistic effluent standards, creates a need to predict the impact of pollution loads on river water quality during critical flow periods or as the result of future user demands. Because of the complexity of aquatic systems, mathematical models are an excellent medium for bringing together the state-of-the-art knowledge from a variety of disciplines into a form which can be readily applied to practical problems. Applying a mathematical model to a river system has the added advantage of providing a structure for the systematic consideration of the many diverse aspects of water quality phenomena. This report describes the development of a river simulation model (QUAL-U) for predicting water quality and its preliminary application to the Weber River drainage basin in northeastern Utah. The model involves the numerical solution of a set of differential equations representing the aquatic system under steady state conditions. The development and use of a second model which provides the flow boundary conditions for the first model is also described. This model is a simple interactive procedure for obtaining flows at specified locations on the river system given the measured flows at other locations and typical flow ranges of headwater, diversions, surface and subsurface lateral inflows, and point loads. Previous river water quality models are reviewed and the structure of QUAL-U is presented. The economic and physical characteristics of the study area are described and the Weber River system is represented by subbasins, reaches, and computational units. Model calibration was based on water quality data collected at over eighty sampling locations in the study area during a four day period in September, 1973. Each of the sampling points was subsequently surveyed to obtain representative hydraulic characteristics for each reach of the river system. Coefficients for the mathematical equations representing hydraulic characteristics and chemical and biological reactions were estimated and adjusted during the model calibration procedure until model responses satisfactorily resembled the observed data. Results for the calibration period and also for studies involving critical low flow conditions are described and model limitations are considered. The work on which this report is based was performed for the State of Utah, Department of Social Services, Division of Health as part of a Waste Load Allocation Study on the Weber River. The scope of this project provided only for supplying the calibrated model to the client and does not include predictive runs or interpretation of management alternatives

Water Quality Management Studies for Water Resources Development in the Bear River Basin

Summary: The quality of water that develops in the proposed reservoirs of the Upper Bear River Storage Project will determine the possible uses of the water. Previous studies of water quality in the Bear River and its tributaries have reported water quality problems relating to nitrate ion, sanitary indicator bacteria, suspended solids, and phosphorus concentrations. Most point sources of water pollution inthe basin have been eliminated or improved in quality, but nonpoint sources of pollution continue to degrade the quality of the Bear River. Concentrations of phosphours have been sufficiently high to encourage dense algal growth and create eutrophic conditions in the proposed impoundments where other factors were not limiting. The present study intended to investigate these problems relative to the potential use of impounded water for municipal and industrial purposes. Past water quality information for the study area of the Bear River basin was reviewed including analysis of 208 areawide planning data and STORET data accumulated by the Utah Bureau of Water Pollution Control since 1977. Salinity components were found to be the major factors describing water quality in the Bear River, but nutrients and microbial pollution indicators were also very important. Nitrate concentrations were not found to have approached the 10 mg N*l^-1 standard in the historical data reviewed. Thirteen monthly water quality sampling and analyses were performed from 15 locations on the Bear River and its tributaries beginning above Oneida Reservoir, Idaho, and extending to the interstate highway bridge near Honeyville, Utah. These data indicate that the Cub River continues to be an important source of nutrients and microbiological pollution to the Bear River. The lower reaches of the Little Bear River occasionally accumulate undesirable concentrations of biochemical oxygen demand, nutrients, and fecal indicator bacteria. Increases in suspended solids and phosphorus loads in the Bear River and its tributaries were observed during spring snowmelt and runoff. Weston Creek, Fivemile Creek, and Deep Creek carried exceptionally high suspended solids and phosphorus loads during this time. A major increase in total phosphorus and orthophosphorus in the Bear River below the confluences of these streams was observed. Landsliding and erosion in the watersheds of these streams probably contribute substantially to their phosphorus and sediment loads. A water temperature model, empirical trophic state models, and a computerized reservoir eutrophical model (RESEN) were used to simulate the eutrophication potential of the proposed reservoirs. Since turbidity is expected to decrease over the length of the reservoirs allowing more light energy for photosynthesis, and since ample phosphorus will be available, the proposed Amalga Reservoir is likely to be eutrophic near the dam and in the Cub River branch. Similarly, the proposed Honeyville Reservoir is likely to be eutrophic near the dam and pools of anoxic water may develop below the thermocline. High populations of zooplankton could reduce summertime algal populations in the Honeyville Reservoir of mesotrophic to eutrophic conditions. Zooplankton grazing has been observed to substantially reduce algal populations in the existing Hyrum Reservoir on the Little Bear River. The proposed Lower Oneida Reservoir in Idaho will probably not thermally stratify, but will have a temperature regime similar to the existing Oneidea Reservoir and remain essentially completely mixed throughout the year. The depth of mixing of the water column is expected to limit algal grwoth and maintain this reservoir in an oligotrophic condition. The proposed Mill Creek and Avon Reservoirs on the Blacksmith Fork and Little Bear Rivers, respectively, will probably produce spring and fall algal blooms of mesotrophic to eutrophic proportions. Strong thermal stratification of these reservoirs in the late spring will isolate the epilimnion from phosphorus sources. Available phosphorus in the epilimnion will be exhausted through algal growth and settling, and phosphourus in the photic zone will not be replaced until destratification occurs in the fall. Reservoirs may remove phosphours from streams by trapping sediment and converting soluble phosphorus to algae or other plants that are retained in the reservoir. Lower phosphorus concentrations in the stream then result in less productive conditions in downstream reservoirs. The proposed upstream reservoirs on the Bear River or its tributaries are not expected to produce an appreciable improvement in downstream reservoirs, however. Phosphorus inputs from tributaries and nonpoint sources will probably negate phosphorus removal by these reservoirs. A study of chemical use by the Little Cottonwood water treatment plant revealed a general independence on raw water quality except for taste and odor. Assuming that water from the Honeyville Reservoir will receive conventional treatment and treatment with permanganate to control taste and odor in the same way as water is treated at the Little Cottonwood plant, treatment costs were estimated to be approximately $80 per acre ft. If trihalomethane compounds are formed from chlorination of the water, and concentrations exceed drinking water standards, treatment costs would increase by$6 to $190 per acre ft depending on the degree of removal required and the treatment method selected. If eutrophic cnoditions can be prevented from developing in the Honeyville Reservoir, concentrations of trihalomethane precursors produced by algal growth and decomposition would be expected to be low, and trihalomethane formation would not be expected to be a problem

Nutrient Dynamics and Gas Production in Aquatic Ecosystems: The Effects and Utilization of Mercury and Nitrogen in Sediment-Water Microcosms

Sixteen sediment-water microcosms designed to allow complete gas, liquid, and solid mass balances of gases, nutrients, and mercury were studies under dark conditions or varying light intensity for a period of 189 days. Results indicated that the microcosm technique is a very sensitive method of analyzing microbial dynamics in sediment water systems. Gas quantity and composition changes were easy to monitor and were especially sensitive to light and nutrient variations. Nitrogen fixation occurred in all lighted systems (blue-green algae nitrogen fixers, Anabaena, and others) and was adequate to insure that no nitrogen limitation occurred even though nitrogen limitation was imposed on the system. Sediments apparently did not act as a significant source of nitrogen. Iron and phosphorus were in excess and as such were closely linked as would be predicted on the basis of chemical equilibria. Non-equilibrium chemical behavior of such elements would apparently result only when appreciable amounts of the compound or element is utilized in growth

Disturbance-diversity relationships in two lakes of similar nutrient chemistry but contrasting disturbance regimes

Phytoplankton diversity was studied in two North German lakes of comparable nutrient chemistry but different exposure to winds. In both lakes, phytoplankton was primarily N-limited but diatoms were Si-limited. Plußsee had a very constant mixing depth during summer, while week-to-week changes of several meters were quite common in the more exposed Behler See. In Plußsee, phytoplankton biomass during summer came closer to the carrying capacity as defined by the available total N. In Plußsee there was a marked decline of diversity during the summer maximum of biomass, while this decline was less pronounced in Behler See. It is concluded that disturbances which prevented phytoplankton from reaching the carrying capacity also maintained a high level of diversity. A negative response of diversity to undisturbed conditions became apparent, after phytoplankton biomass had exceeded about 5% of the carrying capacity

Activity Analysis and the Management of Resources: A Model for Control of Eutrophication.

A model incorporating phosphorus using activities, the relationship between phosphorus loading and eutrophication (Vollenweider, 1968) and the direct costs of treating phosphorus to reduce phosphorus input to surface water was developed. The model can be applied to any region or river basin using rather easily obtainable data. Using Lake Erie as an example, changes in phosphorus input as a result of various management tactics resulted in changes in relative eutrophication. Treatment costs associated with management strategies were related to effectiveness in controlling eutrophication, and the use of cost effectiveness analysis for selecting the most comprehensive set of management factors was demonstrated. The use of activity analysis to control the effects of particular resources, in this case phosphorus, is a reasonable approach. Management of a resource rather than treatment alone should be instituted when the real costs of management controls are less than the treatment costs saved or avoided. In Lake Erie use of management controls can result in significant treatment cost saving and thus implementation of controls appears feasible. A combination of management controls and treatment processes can result in lowering eutrophication levels to somewhere in the mesotrophic range, at least, with respect to phosphorus loading

Fate and Transport of Organics in Soil: Model Predictions and Experimental Results

Laboratory batch reactors were used to generate quantitative information about the fate of polynuclear aromatic hydrocarbon (PNA) compounds in soil systems. First-order degradation rates and equilibrium partition coefficients determined in laboratory studies were used in the Vadose Zone Interactive Processes (VIP) mathematical model to predict the fate and behavior of the PNA compounds as a function of time and soil depth. Predicted model results were compared with independent laboratory soil column studies for model validation. The VIP model provided a good approximation of the degradation and transport of the seven PNA compounds evaluated after 6 months of incubation in soil. Sensitive parameters in the VIP model included degradation rates and initial soil concentrations

Goal Programming Model for Water Quality Planning

The broad goals of the Federal Water Pollution Control Act Amendments (PL 92-500) and the regional nature of water quality plans require that multiple objectives be considered in planning. Goal programming is an extension of linear (or integer) programming where the objective is to minimize the deviations from a set of goals, subject to system constraints. The model is applied to an example river basin system where the planning goals are the quality levels of four constituents required for three desired beneficial water used in five stream reaches, and the budget availability in four municipal regions for financing wastewater treatment. The model solution indicates the combination of treatment levels and costs that minimize deviations from user quality and budgetary goals for all stream reaches. Values of deviation variables in the solution indicate the water quality levels achieved. A comparison with the minimum cost solution for meeting stream standards identifies the costs and tradeoffs of achieving higher user quality goals