A PRELIMINARY QUANTIFICATION OF THE IMPACTS OF ASPEN TO CONIFER SUCCESSION ON WATER YIELD - I. HEAT PULSE METHODOLOGY FOR MODEL CALIBRATION1

ABSTRACT: Twenty-six aspen (Populus tremuloides Michx.), 20 subalpine fir (Abies lasiocarps (Hook.) Nutt.), and 20 Engelmann spruce (Pices engelmanil (Parry) Engelm.) of various sizes were cut under water and suspended in permanent reserviors at a northern Utah site. The reservoirs were asealed so that all water loss was due to consumption by the trees. Sap velocities, as computed from heat pulse velocities, were related to conducting areas of the tree trunks. Computed transpiration volumes were then correlated with actual water losses from the reservoirs. Coefficients of determination (R²) of 0.87, 0.86, and 0.82 were obtained for the fir, aspen, and sprucs, respectively. Reservoir water loss for each species for each season was then used to adjust a plant activity index for computing transpiration within ASPCON, a model describing the hydrology of aspen to conifer succession. The plant activity index reflects the variation in the capability of a plant community to transpire water over the year. Assumptions and limitations of the heat pulse velocity technique are also outlined.     

IMPACTS OF SILVICULTURE ON FLATWOODS RUNOFF,WATER QUALITY,AND NUTRIENT BUDGETS1

ABSTRACT: Three forest watersheds were isolated by roads in poorly drained flatwoods of Florida. After 12 months of baseline calibration the forest in one watershed was harvested and regenerated with minimum disturbance, in the second watershed with maximum disturbance from common practices, and in the third watershed left intact as a control. Water yields from the maximum treatments increased a significant 250 percent while that from the minimum treatments increased 117 percent as compared to the control. Weed vegetation remaining after the minimum treatment continued significant water use. The water yield increases lasted only for one year. Water quality was reduced by both treatments with the most effect immediately after the maximum disturbance. Absolute levels of suspended sediments, potassium, and calcium remained relatively low. The maximum treatment caused significant changes in net cation balances only for one year. The information shows relative little effect of silvicultural practices in flatwoods on water quality as compared to data from upland forests. Water yield increases may be manipulated by the degree of harvest and weed control practices.     

IMPACT OF DROUGHT ON QUALITY OF POTENTIAL WATER SUPPLY SOURCES IN THE SANGAMON RIVER BASIN1

ABSTRACT: The analysis of stream flow and several water quality parameters in six Illinois rivers showed both deterioration and improvement in quality indicators during 1976–1977 drought. The adverse impacts were an increase of ammonia and manganese concentrations and, to a lesser degree, increased concentrations of phenol and specific conductance. At the worst point during the drought, the 12-month moving average of monthly ammonia concentration in the Sangamon River was about 620 percent higher than the antecedent value. On the other hand, average concentrations of nitrites and nitrates, total iron, and the number of coliform bacteria significantly decreased. This positive response suggests that streams which are considered unsuitable for municipal supply due to high levels of these quality indicators may be used as emergency sources during droughts.     

IMPACT ON RESIDENTIAL WATER CONSUMPTION OF AN INCREASING RATE STRUCTURE1

ABSTRACT: A two-step procedure is used to estimate the impact of an increasing rate structure on residential water use. An error components regression procedure is used to estimate demand relationships for a period prior to the rate change. Water use is predicted for the post rate change period, assuming that the rate structure was not changed. Comparison of actual with predicted use indicate that water use declined as a result of the imposition of the increasing rate structure.     

EMERGING CONCEPTS FOR THE CONDUCT OF STATE WATER RESOURES PLANNING1

ABSTRACT: The development of water resources planning at the state level is discussed. Although there are significant specific differences among state planning programs, some common general principles of state water resources planning are emerging over time. In the interest of reconciling conflict over water allocation states are engaged in policy clarification, mediation of interst group conflict, and provision of baseline information.     

IMPACT OF WATER CUTBACK ON SUGARCANE PRODUCTION IN THE FLORIDA EVERGLADES1

ABSTRACT: Sugarcane (Saccharum spp.) was planted in six lysimeters containing Pahokee muck (Lithic Mediaprist) where water tables were maintained at 30, 60, and 90 cm depths. The main objective was to study the impact of a 40 percent water cutback (108 mm) on sugarcane production during the period near the end of the dry season (i.e., May). The water cutback treatment was simulated through manipulation of water table depth. Due to the high available water capacity of the muck soil and selection of a sugarcane cultivar ‘CP63-588’ (which has a high tolerance of water table fluctuations), the sugarcane growth, and the yields of sugarcane biomass and sugar were not significantly different as a result of the treatments with and without 40 percent water cutback during a period of two months. This result is in good agreement with the 1981 cane yield in the Everglades Agricultural Area where a 35 percent water cutback was imposed during the 1981 drought.     

PERCEIVED WATER QUALITY AND THE VALUE OF SEASONAL HOMES1

ABSTRACT: The impact of degraded water quality on the value of seasonal homes adjacent to St. Albans Bay on Lake Champaign in northern Vermont is estimated using hedonic price functions. The Value of properties located adjacent to the bay are depressed by about 20 percent, or $4,500 on average, compared with similar nearby properties on the larger but cleaner lake. Water quality degradation resulted in decressed property values of approximately two million dollars in the area surrounding the Bay.     

CAPITAL COSTS OF RURAL WATER SYSTEMS: AN EMPIRICAL APPROACH1

ABSTRACT: In the last two decades the federal government has provided substantial capital to construct rural water distribution systems. Loans at subsidized interest rates and front-end grants through the Farmers Home Administration have been the main source of this capital. Recent federal policy redirections have reduced substantially the availability of grants and subsidized loans. Because of design and material differences, capital cost estimates from urban systems are not uniformly applicable to rural water services. This study presents an econometric analysis of capital costs, using Illinois rural water system construction contract bids. Cost equations by systems components representing 90 percent of capital costs are estimated. The type of information developed here can be used in initial planning and optimization design models contributing to the efficient provision of rural water services.     

THE ENHANCED ROLE OF WATER CONSERVATION IN THE COST-BENEFIT ANALYSIS OF WATER PROJECTS1

The concept of water conservation has increased in importance because of revisions in the rules and procedures for performing cost-benefit analyses of federal water projects. These revisions include a requirement that nonstructural and water conservation measures be incorporated into economic assessments of projects. Project analyses will now proceed as if water supplies were allocated “most effectively,” that is, to their highest valued uses. A related requirement provides that the net benefits of any project should now be valued using willingness to pay measures. A specific cost-benefit methodology accommodating the revisions is constructed and discussed. Informational requirements for applying this methodology are identified. In addition to being consistent with federal mandates, this technique offers important advantages over the traditional “requirements” approach to water supply planning.     

NATIONWIDE ASSESSMENT OF URBAN RUNOFF IMPACT ON RECEIVING WATER QUALITY1

ABSTRACT: Urban stormwater runoff has been recognized as a potential major contributor of pollution to receiving waters. However the projected high costs of control have prompted an examination of the extent to which these impacts have been documented. A nationwide search was conducted for case studies demonstrating a cause-effect linkage between urban runoff and impairment of beneficial uses in receiving waters. The results indicate that numerous definitions of “impacts” are being used and that few substantive data exist to support many of these allegations. Results of a preliminary impact assessment are presented for the 248 urbanized areas of the United States. Then, the results of more recent efforts to assess these impacts in several case studies are described. This assessment demonstrates the critical need for additional short-term and long-term sampling programs.     

THE EFFECTS OF AGE AND WATER FLUCTUATIONS ON FISH POPULATIONS1

ABSTRACT Two lakes having similar soil types were studied to determine the effects of age and water fluctuations on plankton, benthos and fish populations. Bluff Lake is an older man-made lake which is drawn down in the mid-summer. Oktibbeha County Lake is a young lake and the water levels are maintained. Chemistry data from the two lakes indicate that their chemical properties are very similar. Neither lake would be considered very fertile. Net plankton populations in Bluff Lake and Oktibbeha County Lake were comparable when analyzed on a number of organisms per liter basis. Fluctuations of water levels did not seem to have an effect on the net plankton populations. The benthic population in Bluff Lake is slightly higher than that found in Oktibbeha County Lake. This is true for both numbers and weight per square meter. The species composition of benthic organisms in the two lakes were similar. Based on one-acre samples from each lake, Bluff Lake has a more balanced fish population than does Oktibbeha County Lake. Neither, however, seems to support populations of game fish in which a high percentage of these are in the available or harvestable range. Both lakes contain high populations of gizzard shad.     

CHANGES IN WATER POLICY IN THE PEOPLE'S REPUBLIC OF CHINA1

ABSTRACT: Ideology has predisposed the People's Republic of China against the use of prices to allocate water. Prolonged drought in north China has made the Chinese more aware of their unfavorable water resource inventory and the expense of expanding supply. Therefore, as part of the economic liberalization commenced since the death of Mao Zedong, China has started to make more active use of pricing to regulate demand and reduce the need for supply expansion.     

IMPACT OF DROUGHT ON QUALITY IN A NEW JERSEY WATER SUPPLY SYSTEM1

ABSTRACT. New Jersey, together with other states in the northeast, was stricken with drought during 1961-66. The effect of this drought was most severe in the northern part of the State. The water quality of the Passaic River, which drains the urban, industrialized northeast, perhaps deteriorated the most among the major drainage systems. This river system is used as a raw-water source by 10 water suppliers. The impact of the drought upon the water supply of the Passaic Valley Water Commission, the most downstream of the basin's suppliers, which supplies an average of about 90 million gallons a day to more than 650,000 persons, is evaluated herein. The drought's impact on the raw-water quality is appraised by the comparison of before-and-after qualities of dissolved solids, dissolved oxygen, biochemical-oxygen demand, turbidity, and hardness. For example, at the worst point during the drought, monthly average dissolved-solids content in the raw water were about 210 percent, hardness, about 167 percent, and biochemical-oxygen demand about 270 percent higher than antecedent values. In general, the study concludes that the drought produced a deterioration in both raw and finished water quality, and is estimated to have increased chemical-treatment costs during the drought by about $650,000.     

THE CONTINUING EVOLUTION OF AN AUSTRALIAN WATER RESOURCES POLICY1

ABSTRACT: Australia's extremely limited water resources highlight the need for policy guidelines for management. During the 1970s, there was the gradual evolution of a national water resources policy, facilitated by a nationally agreed statement of objectives and culminating in a federal policy statement presented in 1979. However, the Australian constitution gives major responsibility for water resources to the states. Further, the federal policy statement seems to assume that each state has a water resources policy and that it accords with the nationally agreed objectives. This is not the case, and the practical management of Australia's water resources falls short of the principles set out in the policy document. The River Murray, the nation's major water resource, provides ample evidence of this fact. With very limited water resources, Australia urgently needs to reduce the disparity between principle and practice in their management.     

WATER CONSTRAINTS ON ENERGY DEVELOPMENT: A FRAMEWORK FOR ANALYSIS1

ABSTRACT: The pressure on water resources from energy resource development and transformation is likely to be greater in the future than it has been in the past. A rational resolution of the political problems that this situation will generate requires that: 1) planning based on predictions of future energy supply and demand be replaced by scenario, or “what if?” analysis; 2) full attention be paid to the uncertainties in per-unit-energy water requirements; 3) suitable stochastic measures of water availability be used to compare water supply with water demand; 4) realistic ecological criteria, and other alternative use criteria, be developed for estimating impacts of water withdrawn or consurned for energy development; 5) human consequences of ecological impaccts are described in a manner that will allow the political process to intervene in an optimum manner to allocate water resources.     

DOCUMENTATION OF HIGH SUMMER FLOWS ON THE POTOMAC RIVER FROM THE WOOD ANATOMY OF ASH TREES1

ABSTRACT: Ash trees (Fraxinus americana L. and F. Pennsylvanica Marsh.) collected from the flood plain of the Potomac River near Washington, D.C., were studied for evidence of associations between known periods of above-average summer flows and changes in wood-growth anatomy. Concentric bands of latewood fibers with atypically large lumens and thin walls commonly developed in trees growing near the low-water channel. Discharge records indicate that roots of most trees with these “white rings” were flooded temporarily during the latewood-growth interval. Trees apparently were not damaged and a concomitant reduction of internal water stresses seems to have accelerated the rate of radial growth. The intra-ring position of anomalous fibers generally corresponded to the time of increased discharge within the estimated interval of latewood growth. Anomalous fibers occasionally formed in unflooded trees, but their position also coincided with episodes of increased discharge. The results of these studies may have applications for streamflow-reconstruction techniques where hydrologic data are incomplete or lacking.     

SIMULATION OF WATER POLLUTION GENERATION AND ABATEMENT ON SUBURBAN WATERSHEDS1

ABSTRACT: Computer simulation and model calibration of three “suburban” watersheds near Salt Lake City, Utah, indicate that coliform bacteria and suspended solids are produced mainly by the presence of people, domestic animals, vehicles, disposal systems, and other constructed faclities. The importances of each of these activities is investigated and pollution abatement procedures are outlined for purposes of improved watershed management.     

IMPACTS OF WATER QUALITY IMPROVEMENT ON SITE VISITATION: A PROBABILISTIC MODELING APPROACH1

ABSTRACT: The influence of perceptions of water quality on the likelihood of recreating at a particular recreation site is investigated using a logit model. The model is estimated for St. Albans Bay, Vermont. A hypothetical improvement in water quality was shown to greatly increase the probability of at least one visit to the bay during a season. This implies that many recreationists who do not use the bay at present will do so if water quality improves. A demand model for predicting site visitation must, therefore, include current nonusers in the sample. Failure to do so would result in misleading predictions about future demand for the bay.     

A GEOGRAPHICAL ANALYSIS OF VOTING PATTERNS FOR WATER RELATED CONSTITUTIONAL AMENDMENTS IN TEXAS, 1957-19811

ABSTRACT: Country level electoral data were used to analyze the voting patterns of eight water related constitutional amendment elections. Both water quality enhancement amendments (1971, 1976), and three of six water development amendments (1957, 1962, 1966) have been ratified, thus establishing a statewide policy of reservoir development, a funding mechanism to implement such a policy, and the creation of a water management agency. Begining with the 1969 election, a West Texas-East Texas regionalized voting pattern has emerged, resulting in the defeat of three amendments (1969, 1976, 1981) intended to provide additional funding for water development. This regionalization reflects different climatic, physiographic, economic, and locational factors, and represents a potential obstacle to coordinated water management in Texas.     

THE EFFECTS OF A MOVING RAINSTORM ON DIRECT RUNOFF PROPERTIES1

ABSTRACT: The effects of a moving rainstorm on flood runoff characteristics were investigated. A flood hydrograph simulation model called “FH-Model” and a natural watershed were used. A hypothetical rainstorm of 50 years recurrence interval, 75 mm depth, and 4 hours duration was used to show the effects of velocity and direction of the moving rainstorm on the runoff characteristics. Compared with an equivalent stationary rainstorm (ESRS), the peak flow caused by a rainstorm moving in a downstream direction with a speed equal to channel velocity, V, was 27.5 percent higher and the peak flow caused by the same rainstorm moving in an upstream direction was 21.7 percent smaller. These percentages reduced to 10.5 percent and 8.6 percent for storms moving downstream and upstream, respectively, at three times the channel velocity, 3V. There were negligible differences in the time of peak, T_p between runoff caused by storms moving downstream and runoff produced by ESRS. However, T_p for a storm moving upstream at V velocity was 82 percent higher than that produced by ESRS, but was reduced to 27 percent higher when the storm velocity was 3V.