摘要:

ABSTRACT:The atmosphere is a significant source of plant nutrients that partially replenishes losses due to timber harvesting. The relative importance of wet and dry deposition depends upon the specific nutrient and site. Nitrogen in bulk precipitation (wetfall and dryfall) is equivalent to at least 70 percent of the nitrogen incorporated annually in above‐ground woody tissues of some temperate hardwood forests. Atmospheric sources of calcium and potassium supply between 20 and 40 percent of the nutrients sequestered in woody increments. Annual nutrient inputs in bulk precipitation can exceed removals associated with sawiog harvest over a rotation period. Atmospheric inputs of nitrogen are only slightly less than hydrologic losses immediately after timber harvesting. The deposition of nutrients is highly variable in both time and space; interpretations of nutrient inputs and forest management impacts require quantification of inputs for a variety of ecosystems over long periods of tim

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1984.tb04710.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACT:Data obtained from a limnological survey of 165 Florida lakes were analyzed to determine regional differences in lake color (Pt‐Co units) and relations between color and various physical, chemical, and biological parameters. Average color measurements for the different lakes ranged from 0 to 416 Pt‐Co units with individual measurements being as high as 600 Pt‐Co units. With the exception of extreme south Florida, lake color concentrations were found to increase from north to south and from inland highlands to lowlands. Central Florida had the greatest heterogeneity in lake color because of an extremely diverse geology and physiography. Color was inversely related to Secchi disc transparency and positively related to total iron concentrations. Color was not strongly related to pH, total alkalinity, nutrients, chlorophylla, and many other limnological parameters. Although lakes having color concentrations greater than 20 Pt‐Co units can often be visually identified as colored lakes, the limnological processes in these are not necessarily different from those of lakes having clea

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1984.tb04711.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACT:This paper describes the successful application of a multiobjective planning framework, incorporating substantial public involvement, to a major water resources decision involving intense confilcts. The study was initiated to help resolve more than a decade of controversy over a project proposed to control flooding and provide regulatory storage in the Phoenix, Arizona, area. The public was actively involved in the development of study goals and the specification of acceptable tradeoffs between multiple objectives. A wide range of structural and nonstructural alternatives was formulated and evaluated in relation to these objectives, and broad‐based support was developed for a new plan. Reasons for the successful outcome are discussed, as well as implications for water resources planning under the new Federal Principles and Guideline

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1984.tb04712.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACT:A sensitivity analysis of a computer model, simulating major water and nitrogen processes of a soil‐water‐plant‐climatic system on an annual basis, was conducted to determine how the model reacts to the variations in selected hydrologic and nitrogen parameters. Two major output variables (namely, total subsurface drain volume and cumulative nitrate loss with subsurface drain water) were selected for the sensitivity analysis. Model sensitivity analysis shows that the model is most sensitive to hydrologic parameters. The model is very sensitive to variations in the initial water content in the soil pr

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1984.tb04713.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACT:An index of sediments less than 0.3 mm stored in the top layer of small streams was estimated by disturbing a fixed area for 2 minutes and catching the resultant sediment drift in downstream traps. The method was used in 24 small northern California streams and was tested by releasing known amounts and sizes of sediments in controlled trails. Field use showed general agreement with an exponential model of decrease in sediment trapped vs. distance. Sites in distrubed reaches (watersheds logged with no streamside buffers or with buffers less than 30 m) had higher indices of stored sediment than control sites. Estimates from controlled trials averaged 7.5 percent higher than actual losses for composite size classes ≤ 0.3 mm, 19.7 percent higher than actual losses for just the ≤ 0.125 mm class, and 15.2 percent for all 14 trials. The method is relatively simple and suitable for remote locations, particularly in studies comparing many small stre

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1984.tb04714.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACT:Several large agricultural pumps, located in the upper St. Johns River Basin, Florida, and representative of the numerous pumps operating in the basin, were monitored during the spring and summer of 1982. These pumps have rated capacities ranging from 36 to 334 ft3/s and drain various quantities of improved pasture, row crop, and citrus land uses. The combined total pumping capacity of the pumps in this study is approximately equal to the average flow at US 192, near Melbourne (691 cfs). Results indicate high nutrient and suspended solids loading to the river, but the relative magnitude of each parameter varies with pump site and date. The row crop/Mary A pump (267 ft3/s capacity) exhibited the poorest water quality of the sampled pumps and appeared to have the greatest pollutional potential. The average suspended solids loading rate from the Mary A pump was high (37,900 Kg/day). The average total nitrogen (TN) and total phosphorus (TP) discharge concentrations at this pump were also high, with values of 3.96 mg/L and 0.79 mg/L, respectively. As expected, nutrient loading rates reflected discharge rates, to a large degree. Average TN loading rates for the pumping stations varied from 86 to 1935 Kg/day while TP loading ranged from 7 to 390 Kg/day. Nutrients from pumping are contributing factors to the increasing aquatic plant growth and algal blooms in the area. Poor quality discharge water, as well as rapid rises in water level from the cumulative discharges resulting in dead marsh vegetation and accompanying oxygen sags, have been suggested as causative factors for fish kills in the area.

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1984.tb04715.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTBluegill (Lepotmis macrochirus), largemouth bass (Micropterus salmoides), white catfish (Ictalurus catus), and channel catfish (Ictalurus punctatus), collected from an electric power plant cooling reservoir and a municipal water supply reservoir near Roxboro, North Carolina, were analyzed for selenium concentrations in axial muscle, reproductive and liver tissues. Fishes from the municipal water reservoir had lower selenium concentrations (≤0.2‐2.1 μg/g ‐ wet weight) than found in the cooling reservoir fishes (1.6‐70.0 μg/g ‐ wet weight) but similar distributions of concentrations among the tissues was evident. Selenium was differentially accumulated, with higher concentrations in liver tissues (0.7‐70.0 μg/g ‐ wet weight), followed by female reproductive tissues (0.7‐25.0 μg/g ‐ wet weight), axial muscle tissues (≤0.2‐23.0 μg/g ‐ wet weight) and male reproductive tissues

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1984.tb04716.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACTThe stabilities in water and dry storage of two solid‐state disinfectants (3‐chloro‐4, 4‐dimethyl‐2‐oxazolidinone, agent I, and calcium hypochlorite) have been compared under a variety of conditions. Variables in the study included pH, temperature, and water quality. Agent I is considerably more stable in dry storage and in water, especially at pH 4.5 and 7.0, than is calcium hypochlorite. This is true for solutions of the two compounds in sterile, distilled, deionized, demandfree water or in a synthetic water containing heavy organic load. Prior work in these laboratories concerning use of agent I as a disinfectant for lake water in a laboratory‐scale treatment plant had suggested that agent I has considerable potential for use as an alternative to cholorine gas for water disinfection. The present work suggests that agent I is of sufficient stability to be of use as a solid‐state disinfectant for swimming pools and for potable water f

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1984.tb04717.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACT:A new organic N‐chloramine disinfectant (3‐chloro‐4, 4‐dimethyl‐2‐oxazolidinone, agent I) has been compared with calcium hypochlorite as to its tendency to react with organic matter in water to produce toxic trihalomethanes. Agent I reacts much less readily with organic demand than does calcium hypochlorite. This study shows that agent I should be safe to use as a disinfectant for water containing appreciable organic load in either sunlight or darkness. On the other hand, calcium hypochlorite may not be a satisfactory disinfectant from the toxicity standpoint for water which contains organic load which must be stored for extended time periods in either sunlight

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1984.tb04718.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

ABSTRACT:The Jack Creek watershed, a 133 km2(51.5 mi2) drainage in southwestern Montana, was impacted by a mountain pine beetle (Dendroctonus ponderosaeHopkins) epidemic in 1975–1977 which killed an estimated 35 percent of its total timber. Analyses of USGS streamflow data for four years prior to and five years after mortality suggest a 15 percent post‐epidemic increase in annual water yield, a two‐to three‐week advance in the annual hydrograph, a 10 percent increase in low flows and little increase of peak

ISSN:1093-474X    

DOI:10.1111/j.1752-1688.1984.tb04719.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY