Estimating reference nutrient criteria for Maryland ecoregions

Management of stream nutrients is becoming increasingly important in order to protect both water quality and aquatic resources throughout the USA. Using an extensive water quality database from the long-term Maryland Biological Stream Survey (MBSS), we describe nutrient relationships to landscape characteristics as total nitrogen (TN) and total phosphorus (TP) of small-order, non-tidal streams in USEPA L2 and L3 ecoregions in Maryland and by MBSS stream order at the L2 and L3 ecoregion levels. To protect stream ecosystem integrity, preliminary reference nutrient estimates (TN and TP) as percentiles (25th of all stream reaches and 75th of stream reference reaches) for the six Maryland L3 ecoregions are: Blue Ridge TN 0.29 and 0.64 mg/L, TP 0.0065 and 0.0090 mg/L; Central Appalachians TN 0.40 and 1.0 mg/L, TP 0.0060 and 0.015 mg/L; Middle Atlantic Coastal Plains TN 0.93 and 2.5 mg/L, TP 0.094 and 0.065 mg/L; Northern Piedmont TN 1.6 and 1.8 mg/L, TP 0.010 and 0.015 mg/L; Ridge and Valley TN 0.40 and 0.98 mg/L, TP 0.0063 and 0.012 mg/L; and Southeastern Plains TN 0.33 and 0.82 mg/L, TP 0.016 and 0.042 mg/L. High levels of both TN and TP are present in many streams found in non-tidal watersheds associated with all Maryland ecoregions, but are especially elevated in the Northern Piedmont and Middle Atlantic Coastal Plain ecoregions, with the latter second-order streams (average TN?>?2.9 mg/L) significantly higher than all other ecoregion–order combinations. Across all six ecoregions, mean nutrient loading for both TN and TP was generally equivalent in first-order streams to nutrient concentrations seen in both second- and third-order streams, indicating a definite need to increase efforts in preventing nutrients from entering first-order streams. Small-order stream nutrient levels are the drivers for subsequent TN and TP inputs into the upper freshwater tidal reaches of the Chesapeake Bay, resulting in a potential risk for altered estuarine ecosystems.     

Farmers’ attitudes about farming and the environment: A survey of conventional and organic farmers

Farmers have been characterized as people whose ties to the land have given them a deep awareness of natural cycles, appreciation for natural beauty and sense of responsibility as stewards. At the same time, their relationship to the land has been characterized as more utilitarian than that of others who are less directly dependent on its bounty. This paper explores this tension by comparing the attitudes and beliefs of a group of conventional farmers to those of a group of organic farmers. It was found that while both groups reject the idea that a farmer’s role is to conquer nature, organic farmers were significantly more supportive of the notion that humans should live in harmony with nature. Organic farmers also reported a greater awareness of and appreciation for nature in their relationship with the land. Both groups view independence as a main benefit of farming and a lack of financial reward as its main drawback. Overall, conventional farmers report more stress in their lives although they also view themselves in a caretaker role for the land more than do the organic farmers. In contrast, organic farmers report more satisfaction with their lives, a greater concern for living ethically, and a stronger perception of community. Finally, both groups are willing to have their rights limited (organic farmers somewhat more so) but they do not trust the government to do so.     

THE ECONOMIC VALUE OF GROUND WATER RECHARGE FOR IRRIGATION USE1

ABSTRACT: Artificial recharge as a means of augmenting water sup plies for irrigation is a management alternative which policy makers in ground water decline areas are beginning to consider seriously. A conceptual model is developed to evaluate the economic benefits from ground water recharge under conditions where the major water use is irrigation. The methodology presented separates recharge benefits into two components: pumping cost savings and aquifer extension benefits. This model is then applied to a Nebraska case to approximate the value of recharge benefits as a function of aquifer response. discount rate, and commodity prices. It was found that recharge benefits vary from less than $2 to over $6 an acre foot recharged.     

A MODELING APPROACH FOR STORM WATER QUANTITY AND QUALITY CONTROL VIA DETENTION BASINS1

ABSTRACT: Storm water detention basins have historically been employed for quantity (i.e., flooding) control only. However, recently it has been suggested that these basins may also provide a practical means of storm water quality control. This paper presents the formulation of a mathematical modeling approach which may be used by professionals to simultaneously design detention basins for the dual purpose of storm water quantity and quality control. Model simulations demonstrate that for a given basin, pollutant removal increases as storm frequency increases. The importance of particle size distribution and settling velocity for net pollutant removal is illustrated, The design procedure is demonstrated, and pollutant loading diagrams for estimating pollutant removal as a function of storm size are developed.     

Agricultural area impacts within a natural area: Cades cove,a case history

Agricultural management in Cades Cove, an historic district in Great Smoky Mountains National Park, has affected natural resources both within the district and in the adjoining natural areas. Aquatic impacts of haying and cattle grazing included increases in water temperatures, turbidity, nutrient loading, and bacterial counts and decreases in benthic macroinvertebrate density and fish biomass. Wildlife populations, including groundhogs, wild turkeys, and white-tailed deer, have increased in the open fields and around the periphery of the historic district. Intensive deer foraging has removed deciduous seedlings and saplings from woodlots, lowering species diversity and favoring coniferous reproduction. Cades Cove has limestone habitats unique in the park, and both deer browse and cattle grazing may have disturbed populations of rare plant species. Effects on water quality are detectable at a campground 15 stream km from the agricultural area, and the effects of deer foraging extend about 1 km beyond the open fields.Since historic landscape preservation is presently a goal of the park, managing for open vistas in Cades Cove will require some sort of continuing disturbance. Conversion of cattle pastures to hayfields would reduce aquatic impacts but the deer herd might increase as a result of reduced competition for forage. Retarding old field succession would increase populations of native plant species dependent on sunlight, but would require government-funded mowing. Other options are discussed. Completely eliminating the effects of the historic district on adjoining areas may be impossible, at least under present economic constraints.     

WATER SAVINGS FROM LAWN WATERING RESTRICTIONS DURING A DROUGHT YEAR,FORT COLLINS,COLORADO1

ABSTRACT: During the drought year of 1977, unusually low river flows during the summer caused the City of Fort Collins, Colorado, to institute lawn watering restrictions for six weeks as a conservation measure. Water use during the restriction period decreased 41 percent below the previous year. The effectiveness of the restrictions, however, has been unclear because abnormally wet weather also appeared to reduce evapotranspiration rates during the period the restrictions were in effect. The statistical analysis indicates that the reduction in water use due to lawn watering restrictions was 603 acre-feet and that abnormal weather reduced use by an additional 659 acre-feet during the same period. During a period of normal evapotranspiration rates, such restrictions would be expected to reduce Fort Collins municipal water usage by 19.7 percent.     

DETERMINISTIC MODELS FOR PREDICTING RESIDENTIAL WATER CONSUMPTION1

ABSTRACT: Forecasts of future urban water demand traditionally have been made by the projection of historic trends in per capita consumption and population. This paper outlines the use of two deterministic models to forecast the residential component of urban water demand. The models incorporate specific representation of the activities which result in water consumption at each residence. Predictions of water use can then be made by modeling the changes expected in the number of these activities and the consumption for each such activity.