KALMAN FILTER ESTIMATION AND PREDICTION OF DAILY STREAM FLOWS: I. REVIEW,ALGORITHM, AND SIMULATION EXPERIMENTS1

An important class of models, frequently used in hydrology for the forecasting of hydrologic variables one or more time periods ahead, or for the generation of synthetic data sequences, is the class of autoregressive(AR) models. As the AR models belong to the family of linear stochastic difference equations, they have both a deterministic and a stochastic component. The stochastic component is often assumed to have a Gaussian distribution. It is well known that hydrologic observations (e.g., stream flows) are heavily affected by noise. To account explicitly for the observation noise, the linear stochastic difference equation is expressed in state variable form and an observation model is introduced. The discrete Kalman filter algorithm can then be used to obtain estimates of the state variable vector. Typically, in hydrologic systems, model parameters, system noise statistics and measurement noise statistics are unknown, and have to be estimated. In this study an adaptive algorithm is discussed which estimates these quantities simultaneously with the state variables. The performance of the algorithm is evaluated by using simulated data.     

URBAN RUNOFF: POLLUTION SOURCES,CONTROL, AND TREATMENT1

This paper reviews progress on urban storm water management and pollution control, with emphasis on non- and low-structurally intensive techniques along with the total system approach encompassing control-treatment. Many of the U.S. Environmental Protection Agency's demonstration-evaluation projects are presented to exemplify: Land Management Techniques, i.e., land use planning, best use of natural drainage, dual use of retention and drainage facilities required for flood control designed concurrently or retrofitted for pollution control, porous pavement, surface sanitation, and chemical use control; Collection Systems Control, i.e., catchbasin cleaning, flow regulators (including swirl and helical devices), and the new concepts of elimination or reduction of unauthorized cross-connections, in-channel/conduit storage and/or other forms of storage for bleed-back to existing treatment plants; Storage including in-receiving water storage; Treatment, i.e., physical/chemical, disinfection, and a treatment-control planning and design guidebook; Sludge and Solids Residue from Treatment; and Integrated Systems, i.e., storage/treatment, dual-use wet-weather flow/dry-weather flow facilities, and reuse of stormwater for nonpotable purposes. Recommendations for the future in the areas of: control based on receiving water impacts, toxics characterization and their control, sewer system cross-connections, integrated stormwater management, and institutional/sociological/economic conflicts are also presented.     

DEVELOPMENT AND MANAGEMENT OF LAND/WATER RESOURCES: THE EVERGLADES,AGRICULTURE, AND SOUTH FLORIDA1

ABSTRACT: South Florida and the Everglades have been under intensive development since 1850 by Federal and State governments who encouraged and financed extensive drainage and hydraulic changes, primarily for agricultural settlement. Agricultural development of the sugar industry in the northern Everglades adjacent to Lake Okeechobee rapidly progressed only after the 1900s. Political and resource management conflicts have arisen because policies which once favored development are now being reversed by policies and regulation efforts to restore and conserve natural ecosystems. Currently, the environmental and ecological impacts of agricultural land use adjacent to natural wtlands of the Everglades are being assessed. The objectives of this paper are: (1) to outline the historical development of south Florida and the sugar industry, (2) to relate this history to political and management policy changes occurring as it pertains to ecosystem restoration and the multiuser competition for water/land resources, and (3) to propose how integrated resource management might be utilized for a sustainable Everglades and south Florida. This paper outlines the historical paradox of urban settlement, land development, and agricultural production, with efforts in the recent decade to acquire, manage, and preserve land and water resources for natural areas conservation. Only though the use of integrated resource management will the defined resource conflicts be mediated.     

ENVIRONMENTAL CONCERN: CONCEPTUAL DEFINITIONS, MEASUREMENT METHODS, AND RESEARCH FINDINGS

A serious threat to human beings and their environment is the continuous and accelerating overuse and destruction of natural resources. Bearing this in mind, it is unfortunate that efforts to permanently change people's environmentally destructive behaviour through interventions has typically not been met with success. A necessary condition may be an increase in environmental concern and knowledge about the effects and consequences of the ongoing environmental deterioration for future generations. Studies are reviewed that have attempted to show (1) correlations between determinants, such as socio-demographic and/or psychological factors, and environmental concern, and (2) an impact of environmental concern on environmentally responsible behaviour. In general, correlations with background factors are weak. Factors affecting behaviour appear to be knowledge, internal locus of control (positive control beliefs), personal responsibility, and perceived threats to personal health. The need for further research that attempts to specify the process leading to environmentally responsible behaviour is highlighted. A new framework is presented which integrates some of the previous research.     

TEMPORAL AND GEOMORPHIC VARIATIONS OF STREAM STABILITY AND MORPHOLOGY: MAHOGANY CREEK,NEVADA1

ABSTRACT: Detailed studies of long-term management impacts on rangeland streams are few because of the cost of obtaining detailed data replicated in time. This study uses government agency aquatic habitat, stream morphologic, and ocular stability data to assess land management impacts over four years on three stream reaches of an important rangeland watershed in northwestern Nevada. Aquatic habitat improved as riparian vegetation reestablished itself with decreased and better controlled livestock grazing. However, sediment from livestock disturbances and road crossings and very low stream flows limited the rate of change. Stream type limited the change of pool variables and width/depth ratio, which are linked to gradient and entrenchment. Coarse woody debris removal due to previous management limited pool recovery. Various critical-element ocular stability estimates represented changes with time and differences among reaches very well. Ocular stability variables tracked the quantitative habitat and morphologic variables well enough to recommend that ocular surveys be used to monitor changes with time between more intensive aquatic surveys.     

FRONTIER AREAS, RESOURCES, AND DEVELOPING NATIONS: THE CASE OF GUATEMALA

The conscientious and planned integration of frontier areas into the national economy can at least partially alleviate both environmental and economic problems that are common to many developing countries. Full development of the agricultural potential of frontier areas can lessen the environmental deterioration often found in traditionally settled regions. Exploitation of mineral resources, in particular energy resources, can lessen economic burdens associated with increased costs of imported energy. The authors examine how recent international developments have spurred the government of Guatemala to undertake measures designed to develop a previously underutilized region. The short term negative consequences of increased costs for imported grains and petroleum may well have a positive result in the long term insofar as they lead to more balanced and rational use of land and resources.     

CITIZEN INFLUENCE IN WATER POLICY DECISIONS: CONTEXT, CONSTRAINTS, AND ALTERNATIVES

ABSTRACT: The desirable proportion of citizen input into policy making and the proper mechanism for that input engender substantial conflict in the water resources arena. Nevertheless, discussions of citizen participation in water policy formation generally occur within narrow perspectives both with regard to the issues involved and the alternative mechanisms by which that participation can be realized. This paper examines the historical and current contexts of the controversies and presents a discussion of the alternative processes for citizen influence - called linkage. The linkage processes discussed include direct participation, citizen advisory committees, the pressure group model, the electoral model and the bureaucratic model. Each linkage process is discussed in terms of who is considered the public, how the public influence works, the limitations of the process, and what available water policy-related data suggest regarding the adequacy of the process.     

REVIVING URBAN STREAMS: LAND USE,HYDROLOGY, BIOLOGY,AND HUMAN BEHAVIOR1

ABSTRACT: Successful stream rehabilitation requires a shift from narrow analysis and management to integrated understanding of the links between human actions and changing river health. At study sites in the Puget Sound lowlands of western Washington State, landscape, hydrological, and biological conditions were evaluated for streams flowing through watersheds with varying levels of urban development. At all spatial scales, stream biological condition measured by the benthic index of biological integrity (B‐IBI) declined as impervious area increased. Impervious area alone, however, is a flawed surrogate of river health. Hydrologic metrics that reflect chronic altered streamflows, for example, provide a direct mechanistic link between the changes associated with urban development and declines in stream biological condition. These measures provide a more sensitive understanding of stream basin response to urban development than do treatment of each increment of impervious area equally. Land use in residential backyards adjacent to streams also heavily influences stream condition. Successful stream rehabilitation thus requires coordinated diagnosis of the causes of degradation and integrative management to treat the range of ecological stressors within each urban area, and it depends on remedies appropriate at scales from backyards to regional storm water systems.     

OPTICAL IMPACTS AND SOURCES OF SUSPENDED SOLIDS IN ONONDAGA CREEK,U.S.A.1

ABSTRACT: The degradation of the optical aesthetics in the mouth of Onondaga Creek, New York, that occurs during high flow periods as a result of the influx of large quantities of suspended solids, is documented. Features of the degradation include very low clarity (Secchi disc minimum of approximately 0.1 m) and a brown ‘muddy’ appearance. The reduced clarity is mostly a result of increased light scattering. Loading and concentration profiles obtained for an approximately 35 km interval above the creek mouth over a wide range of flow indicates most of the suspended solids received during runoff events is resuspended stream sediment and eroded bank material. Application of microscopy-based individual particle analysis techniques indicates that the origin of most of these deposits and much of the suspended solids during runoff events is point source inputs, termed ‘mud boils,’ located approximately 32 km upstream of the creek mouth.     

LANDSCAPE‐SCALE ANALYSIS AND MANAGEMENT OF CUMULATIVE IMPACTS TO RIPARIAN ECOSYSTEMS: PAST,PRESENT, AND FUTURE1

ABSTRACT: Analyses of cumulative impacts to riparian systems is an important yet elusive goal. Previous analyses have focused on comparing the number of hectares impacted to the number of hectares restored, without addressing the loss of riparian function or the effect of the spatial distribution of impacts. This paper presents an analysis of the spatial distribution of development‐related impacts to riparian ecosystems, that were authorized under Section 404 of the Clean Water Act. Impacts on habitat structure, contiguity, and landscape context were evaluated using functional indices scaled to regional reference sites. Impact sites were mapped using GIS and analyzed for spatial associations. Positive spatial autocorrelation (i.e. clustering of impact sites) resulted from the piecemeal approach to impact assessment, which failed to prevent cumulative impacts. Numerous small projects in close proximity have resulted in adverse impacts to entire stream reaches or have fragmented the aquatic resources to a point where overall functional capacity is impaired. Additionally, the ecological functions of unaffected areas have been diminished due to their proximity to degraded areas. A proactive approach to managing cumulative impacts is currently being used in Orange County, California as part of a Corps of Engineers sponsored Special Area Management Plan (SAMP). The SAMP process is evaluating the ecological conditions and physical processes of the study watersheds and attempting to plan future development in a manner that will guard against cumulative impacts.     

REGIONALIZATION AND PREDICTION OF FLOODS IN THE FRASER RIVER CATCHMENT,B.C.1

Probability distributions that model the return periods of flood characteristics derived from partial duration series are proposed and tested in the Fraser River catchment of British Columbia. Theoretical distributions describing the magnitude, duration, frequency and timing of floods are found to provide a goof fit to the observed data. The five estimated parameters summarizing the flood characteristics of each basin are entered into a discriminant analysis procedure to establish flood regions. Three regions were identified, each displaying flood behavior closely related to the physical conditions of the catchment. Within each region, regression equations are obtained between parameter values and basin climatic and physiographic variables. These equations provide a satisfactory prediction of flood parameters and this allows the estimation of a comprehensive set of flood characteristics for areas with sparse hydrologic information.     

NUTRIENT MASS BALANCE AND TRENDS,MOBILE RIVER BASIN,ALABAMA, GEORGIA,AND MISSISSIPPI1

ABSTRACT: A nutrient mass balance — accounting for nutrient inputs from atmospheric deposition, fertilizer, crop nitrogen fixation, and point source effluents; and nutrient outputs, including crop harvest and storage — was calculated for 18 subbasins in the Mobile River Basin, and trends (1970 to 1997) were evaluated as part of the U.S. Geological Survey National Water Quality Assessment (NAWQA) Program. Agricultural nonpoint nitrogen and phosphorus sources and urban nonpoint nitrogen sources are the most important factors associated with nutrients in this system. More than 30 percent of nitrogen yield in two basins and phosphorus yield in eight basins can be attributed to urban point source nutrient inputs. The total nitrogen yield (1.3 tons per square mile per year) for the Tombigbee River, which drains a greater percentage of agricultural (row crop) land use, was larger than the total nitrogen yield (0.99 tons per square mile per year) for the Alabama River. Decreasing trends of total nitrogen concentrations in the Tombigbee and Alabama Rivers indicate that a reduction occurred from 1975 to 1997 in the nitrogen contributions to Mobile Bay from the Mobile River. Nitrogen concentrations also decreased (1980 to 1995) in the Black Warrior River, one of the major tributaries to the Tombigbee River. Total phosphorus concentrations increased from 1970 to 1996 at three urban influenced sites on the Etowah River in Georgia. Multiple regression analysis indicates a distinct association between water quality in the streams of the Mobile River drainage basin and agricultural activities in the basin.     

NORTH AMERICAN INTERSTATE WEATHER MODIFICATION COUNCIL: NEED,GOALS, PURPOSE,AND ACTIVITIES1

ABSTRACT: A need for the prudent design and critical analysis of all weather modification efforts was expressed by the attendees of the June 1974 Governors' Weather Modification Conference in Sioux Falls, South Dakota. The attendees also expressed a need for an organization to coordinate and cooperate in intrastate, interstate and possible international weather modification activities, particularly in view of the growing importance of agricultural production, energy demand and domestic water supply. The North American Interstate Weather Modification Council (NAIWMC) was ratified on January 17, 1975, in Denver, Colorado, with its main purpose to achieve and maintain state and local control of such activities while endeavoring to attain a high degree of legislative uniformity and an effective information exchange mechanism. The need, goals, and objectives of the newly-created Council are summarized herein. The by-laws of the Council are presented according to the articles adopted at the organizational meeting. Membership in the Council is available to all states of the United States of America, Mexico, and all provinces of Canada. The officers of the Council are elected from its membership according to the regions of weather modification activities. A summary of the Council's progress at performing the purposes is presented in this paper. Definition of the users involved in the North American Interstate Weather Modification Council has been achieved during the early activities of the Council. The Council's views on federal and state weater modification legislation are presented according to position statements that have been adopted by the member states and provinces.     

EFFLUENT IRRIGATION OF PARA GRASS: WATER,NITROGEN, AND BIOMASS BUDGETS1

Para grass, irrigated with secondary domestic sewage effluent, showed excellent response for disposal of large amounts of water, effective nitrogen removal, and high production of excellent fodder. This grass is found throughout the tropics and parts of the subtropics. It endures flooding and forms dense, easily maintained stands. This is the first time its use has been reported for effluent irrigation. Water, nitrogen, and biomass budgets over a 17-month period were measured in eight percolate style lysimeters. Under irrigation rates as great as 98 mm/day, five days/week, evapo-transpiration averaged 4.6 mm/day. With nitrogen applications of 130 to 2,600 kg/ha/yr, ≥ 79 percent of applied nitrogen was harvested in the grass; 3 percent percolated; and ≤ 28 percent was denitrified. With the highest effluent irrigation rates, nitrate-nitrogen levels remained below the 10 mg/L maximum recommended for potable water. Crop productivity for full effluent treatments averaged 110 t/ha/yr, dry weight. Maximum calculated crude protein content was 13 percent. No nitrate-nitrogen level in the forage exceeded 0.1 percent.     

ESTIMATES OF MEAN CHLOROPHYLL-a CONCENTRATION: PRECISION,ACCURACY, AND SAMPLING DESIGN1

ABSTRACT: Data from 56 north-temperate lakes and reservoirs are used to develop models predicting temporal variance as a function of the mean chlorophyll-a concentration. Trophy, as estimated by mean chlorophyll-a concentration, is shown to have little effect on the sampling effort required to achieve a pre-determined level of precision for lakes sampled year-round. Collecting ten observations results in a coefficient of variation that averaged 20 percent; collecting more than ten observations yields increasingly marginal improvements in precision. The same guidelines apply to mesotrophic or eutrophic lakes sampled in the summer, whereas oligotrophic lakes sampled in the summer require fewer observations to achieve the same level of precision. The bias resulting from collecting too few observations is minimized if five or more observations are collected.