CUMULATIVE IMPACTS OF LANDUSE ON WATER QUALITY IN A SOUTHERN APPALACHIAN WATERSHED1

ABSTRACT: Water quality variables were sampled over 109 weeks along Coweeta Creek, a fifth-order stream located in the Appalachian mountains of western North Carolina. The purpose of this study was to observe any changes in water quality, over a range of flow conditions, with concomitant downstream changes in the mix of landuses. Variables sampled include pH, HCO₃^2?, conductivity, NO₃^?_?-N, NH₄⁺-N, PO₄^3?-P, C1^?-, Na, K, Ca²⁺, Mg²⁺, SO₄^2?, 5iO₂, turbidity, temperature, dissolved oxygen, total and fecal coliform, and focal streptococcus. Landcover/landuse was interpreted from 1:20,000 aerial photographs and entered in a GIS, along with information on total and paved road length, building location and density, catchment boundaries, hydrography, and slope. Linear regressions were performed to relate basin and near-stream landscape variables to water quality. Consistent, cumulative, downstream changes in water quality variables were observed along Coweeta Creek, concomitant with downstream, human-caused changes in landuse. Furthermore, larger downstream changes in water quality variables were observed during stormflow when compared to baseflow, suggesting cumulative impacts due to landscape alteration under study conditions were much greater during storm events. Although most water quality regulations, legislation, and sampling are promulgated for baseflow conditions, this work indicates they should also consider the cumulative impacts of physical, chemical, and biological water quality during stormflow.     

AUTUMN CHEMISTRY OF OREGON COAST RANGE STREAMS1

ABSTRACT: During an autumn runoff event we sampled 48 streams with predominantly forested watersheds and igneous bedrock in the Oregon Coast Range. The streams had acid neutralizing capacities (ANC) > 90 μeq/L and pH > 6.4. Streamwater Na ⁺, Ca^{2 +}, and Mg^{2 +} concentrations were greater than K ⁺ concentrations. Anion concentrations generally followed the order of Cl^- > NO₃^- > SO₄^2-. Chloride and Na ⁺ concentrations were highest in samples collected in streams near the Pacific Ocean and decreased markedly as distance from the coast increased. Sea salt exerted no discernible influence on stream water acid-base status during the sampling period. Nitrate concentrations in the study streams were remarkably variable, ranging from below detection to 172 μeq/L. We hypothesize that forest vegetation is the primary control of spatial variability of the NO₃^- concentrations in Oregon Coast Range streams. We believe that symbiotic N fixation by red alder in pure or mixed stands is the primary source of N to forested watersheds in the Oregon Coast Range.     

FATE OF NITROGEN AND PHOSPHORUS ENTERING A GULF COAST FRESHWATER LAKE: A CASE STUDY1

ABSTRACT: Nitrogen and P fluxes, transformations and water quality functions of Lake Verret (a coastal Louisiana freshwater lake), were quantified. Ortho-P, total-P, NH₄⁺-N NO₃ -N and TKN in surface water collected from streams feeding Lake Verret averaged 104, 340, 59, 185, and 1,060 mg 1^?1, respectively. Lake Verret surface water concentrations of ortho-P, total-P, NH⁺-N, NO₃^?_-N and TKN averaged 66, 191, 36, 66, and 1,292 μg 1^?1. The higher N and P concentrations were located in areas of the lake receiving drainage. Nitrification and denitrification processes were significant in removing appreciable inorganic N from the system. In situ denitrification rates determined from acetylene inhibition techniques show the lake removes 560 mg N m^?2 yr^?1. Laboratory investigations using sediment receiving 450 μg NH⁺₄-N (N-15 labeled) showed that the lake has the potential to remove up to 12.8 g N m^?2 yr^?1. Equilibrium studies of P exchanges between the sediment and water column established the potential or adsorption capacity of bottom sediment in removing P from the overlying water. Lake Verret sediment was found to adsorb P from the water column at concentrations above 50 μg P 1^?1 and the adsorption rates were as great as 300 μg P cm^?2 day^?1 Using the ¹³⁷C s dating techniques, approximately 18 g N m^?2 yr^?1 and 1.2 g P m^?2 yr^?1 were removed from the system via sedimentation. Presently elevated nutrient levels are found only in the upper reaches of the lake receiving nutrient input from runoff from streams draining adjacent agricultural areas. Nitrification, denitrification, and adsorption processes at the sediment water interface over a relatively short distance reduces the N and P levels in the water column. However, if the lake receives additional nutrient loading, elevated levels will likely cover a larger portion of the lake, further reducing water quality in the lake.     

FIRST-YEAR EFFECTS OF CLEARCUTTING AN OAK-HICKORY WATERSHED ON WATER YIELD1

ABSTRACT: Two intermittent streams on oak-hickory watersheds in southern Illinois were gaged with a V-notch weir and sampled with an automatic water sampler. Baseline data was collected for a period of three years. Flow volume showed large variations between years and watersheds. Water samples were analyzed for Na, K, Ca, Mg, ortho-P, and NO₃-N. Water quality was consistently high, but there were significant differences between the watersheds during the calibration period. One watershed was clearcut in November 1979. One year of postharvest data has been analyzed. Flow volume increased 95 percent, but there was no evidence of increased sedimentation. There were significant increases in the stream water concentrations of K, Mg, and NO₃-N of 18 percent, 8 percent, and 274 percent, respectively. Nutrient budgets for the site were not adversely affected by the harvest. The clearcutting operation appears to have had a small impact on the watershed due to minimal disturbance during the logging and below normal precipitation the first year following the harvest.     

Soil Changes Induced by Rubber and Tea Plantation Establishment: Comparison with Tropical Rain Forest Soil in Xishuangbanna, SW China

Over the past thirty years, Xishuangbanna in Southwestern China has seen dramatic changes in land use where large areas of tropical forest and fallow land have been converted to rubber and tea plantations. In this study we evaluated the effects of land use and slope on soil properties in seven common disturbed and undisturbed land-types. Results indicated that all soils were acidic, with pH values significantly higher in the 3- and 28-year-old rubber plantations. The tropical forests had the lowest bulk densities, especially significantly lower from the top 10?cm of soil, and highest soil organic matter concentrations. Soil moisture content at topsoil was highest in the mature rubber plantation. Soils in the tropical forests and abandoned cultivated land had inorganic N (IN) concentrations approximately equal in NH₄ ⁺-N and NO₃ ^?-N. However, soil IN pools were dominated by NH₄ ⁺-N in the rubber and tea plantations. This trend suggests that conversion of tropical forest to rubber and tea plantations increases NH₄ ⁺-N concentration and decreases NO₃ ^?-N concentration, with the most pronounced effect in plantations that are more frequently fertilized. Soil moisture content, IN, NH₄ ⁺-N and NO₃ ^?-N concentrations within all sites were higher in the rainy season than in the dry season. Significant differences in the soil moisture content, and IN, NH₄ ⁺-N and NO₃ ^?-N concentration was detected for both land uses and sampling season effects, as well as interactions. Higher concentrations of NH₄ ⁺-N were measured at the upper slopes of all sites, but NO₃ ^?-N concentrations were highest at the lower slope in the rubber plantations and lowest at the lower slopes at all other. Thus, the conversion of tropical forests to rubber and tea plantations can have a profound effect on soil NH₄ ⁺-N and NO₃ ^?-N concentrations. Options for improved soil management in plantations are discussed.     

EFFECTS OF LAND COVER AND GEOLOGY ON STREAM CHEMISTRY IN WATERSHEDS OF CHESAPEAKE BAY1

ABSTRACT: We measured the base‐flow stream chemistry in all the major physiographic provinces of the Chesapeake Bay drainage basin. The spatial variation of stream chemistry was closely related to differences in geology and land cover among the sampled watersheds. Some stream chemistry variables were strongly affected by geological settings in the watersheds while others were more influenced by land cover. The effects of land cover differed among chemical constituents and regions. Concentrations of Ca²⁺, Mg²⁺, pH, total alkalinity, and conductivity were mainly functions of carbonate bedrock, especially in the Great Valley. Nitrate‐N and total dissolved N were closely related to cropland and increased as the percentage of cropland increased. The rate of increase varied from region to region with the highest in the Piedmont. Na⁺ and Cl^? were mainly affected by the percentage of developed area in a watershed, especially in the Coastal Plain and Piedmont. We observed no significant effects of region or land cover on species of phosphorus because samples were collected under base flow conditions and only dissolved forms were measured. Dissolved silicate (DSi) was not related to any other water chemistry variables. DSi increased as developed area decreased and cropland increased in the Coastal Plain, but these patterns were reversed in the Piedmont. There was no consistent pattern in the spatial variation of land cover effects on the reduced forms of N, dissolved organic P, dissolved organic matter, and K⁺.     

HYDROLOGICAL AND GEOCHEMICAL TRENDS AND PATTERNS IN THE UPPER RIO GRANDE, 1975 TO 19991

ABSTRACT: Hydrological and geochemical spatial patterns and temporal trends were analyzed using U.S. Geological Survey (USGS) water quality data collected from 1975 to 1999 along the uppermost 600 km of the Rio Grande in Colorado and New Mexico. Data on discharge, specific conductivity (SC), total dissolved solids (TDS), pH, Ca²⁺, Na⁺, Mg²⁺, K⁺, HCO₃^?, SO₄^2‐, Cl^?, F^?, and SiO₂ came from six USGS stations ranging from the Colorado‐New Mexico border to below Albuquerque, New Mexico. Linear regression, Kendall's S, and Seasonal Kendall's S’ were used to detect trends, and ANOVA was used to analyze spatial differences between stations. Statistically significant increasing trends occurred in SC, TDS, Ca²⁺, Na⁺, Mg²⁺, K⁺, Cl^?, and F^?in the uppermost reaches, and significant decreasing trends of SC, TDS, Ca²⁺, Mg²⁺, K⁺, HCO₃^?, and SO₄^2‐occurred at the lower stations around Albuquerque. Both fluoride concentrations and pH values increased at and below Albuquerque over the study period. Discharge data show an increasing trend across all stations. Spatially, data for dissolved substances show generally linear upstream to downstream increases in concentrations in the upper four stations, with several notable nonlinear increases at and below Albuquerque (SC, TDS, Na⁺, Cl^?). Significant increases in pH appear at and below Albuquerque, relative to upstream stations, probably due to improved sewage treatment.     

EFFECTS OF FOREST HERBICIDE APPLICATIONS ON STREAMWATER CHEMISTRY IN SOUTHWESTERN BRITISH COLUMBIA1

ABSTRACT: The herbicide glyphosate was applied to portions of two watersheds in southwestern British Columbia to kill vegetation that was competing with Pseudotsuga menziesii (Douglas-fir) plantations. This application had little significant effect on streamwater chemistry (K⁺, Na²⁺, Mg²⁺, Ca²⁺, Cl^-, NOs₃^-, NH₄⁺, PO4^3-, SO₄⁼, and SiO₂ concentrations, electrical conductivity, and pH) when vegetation cover in a watershed was reduced by 4%, but had significant (P>0.05) effects, which lasted for at least five years, when cover was reduced by 43%. In this case, most parameters increased in value following the application, with K⁺ and Mg²⁺ concentrations and pH values exhibiting the most prolonged increases and NO₃^- concentrations exhibiting the greatest percentage increases. Sulphate and dissolved SiO₂ concentrations decreased following the application. Streamwater chemical fluxes showed similar trends to concentrations except that changes in fluxes were less significant and no decreases were observed. Forest management induced losses of NO₃-N in streamwater during the first five post-treatment years in the study area decreased in the order: herbicide application (approximately 40 kg/ha) < clearcutting and slashburning (approximately 20 kg/ha) < clearcutting (approximately 10 kg/ha). In watersheds similar to those of the study area, herbicide application is likely to have a greater impact on streamwater chemistry, in general, than would clearcutting or clearcutting followed by slashburning.     

COALBED METHANE PRODUCT WATER CHEMISTRY IN THREE WYOMING WATERSHEDS1

ABSTRACT: The Powder River Basin in Wyoming has become one of the most active areas of coalbed methane (CBM) development in the western United States. Extraction of methane from coalbeds requires pumping of aquifer water, which is called product water. Two to ten extraction wells are manifolded into one discharge point and product water is released into nearby unlined holding ponds. The objective of this study was to evaluate the chemistry, salinity, and sodicity of CBM product water at discharge points and associated holding ponds as a function of watershed. The product water samples from the discharge points and associated holding ponds were collected from the Cheyenne River (CHR), Belle Fourche River (BFR), and Little Powder River (LPR) watersheds during the summers of 1999 and 2000. These samples were analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS), alkalinity, sodium (Na), calcium (Ca), magnesium (Mg), potassium (K), sulfate (SO₄^2‐), and chloride (C^1‐). From the chemical data, practical sodium adsorption ratio (SARp) and true sodium adsorption ratio (SARt) were calculated for the CBM discharge water and pond water. The pH, EC, TDS, alkalinity, Na, Ca, Mg, K, SARp, and SARt of CBM discharge water increased significantly moving north from the CHR watershed to the LPR watershed. CBM discharge water in associated holding ponds showed significant increases in EC, TDS, alkalinity, Na, K, SARp, and SARt moving north from the CHR to the LPR watershed. Within watersheds, the only significant change was an increase in pH from 7.21 to 8.26 between discharge points and holding ponds in the LPR watershed. However, the LPR and BFR exhibited larger changes in mean chemistry values in pH, salinity (EC, TDS), and sodicity (SAR) between CBM product water discharges and associated holding ponds than the CHR watershed. For instance, the mean EC and TDS of CBM product water in LPR increased from 1.93 to 2.09 dS/m, and froml,232 to 1,336 mg/L, respectively, between discharge and pond waters. The CHR exhibited no change in EC, TDS, Na, or SAR between discharge water and pond water. Also, while not statistically significant, mean alkalinity of CBM product water in BFR and LPR watersheds decreased from 9.81 to 8.01 meq/L and from 19.87 to 18.14 meq/L, respectively, between discharge and pond waters. The results of this study suggest that release of CBM product water onto the rangelands of BFR and LPR watersheds may precipitate calcium carbonate (CaCO₃) in soils, which in turn may decrease infiltration and increase runoff and erosion. Thus, use of CBM product water for irrigation in LPR and BFR watersheds may require careful planning based on water pH, EC, alkalinity, Na, and SAR, as well as local soil physical and chemical properties.     

NITROGEN AND PHOSPHORUS CONCENTRATIONS IN FOREST STREAMS OF THE UNITED STATES1

ABSTRACT: Seventy to eighty percent of the water flowing in rivers in the United States originates as precipitation in forests. This project developed a synoptic picture of the patterns in water chemistry for over 300 streams in small, forested watersheds across the United States. Nitrate (NO₃^?) concentrations averaged 0.31 mg N/L, with some streams averaging ten times this level. Nitrate concentrations tended to be higher in the northeastern United States in watersheds dominated by hardwood forests (especially hardwoods other than oaks) and in recently harvested watersheds. Concentrations of dissolved organic N (mean 0.32 mg N/L) were similar to those of NO₃～, whereas ammonium (NH₄⁺) concentrations were much lower (mean 0.05 mg N/L). Nitrate dominated the N loads of streams draining hardwood forests, whereas dissolved organic N dominated the streams in coniferous forests. Concentrations of inorganic phosphate were typically much lower (mean 12 mg P/L) than dissolved organic phosphate (mean 84 mg P/L). The frequencies of chemical concentrations in streams in small, forested watersheds showed more streams with higher NO₃^? concentrations than the streams used in national monitoring programs of larger, mostly forested watersheds. At a local scale, no trend in nitrate concentration with stream order or basin size was consistent across studies.     

Evaluation of spatial and temporal variation in water quality by pattern recognition techniques: A case study on Jajrood River (Tehran,Iran)

In this paper, principal component analysis (PCA) and hierarchical cluster analysis (CA) methods have been used to investigate the water quality of Jajrood River (Iran) and to assess and discriminate the relative magnitude of anthropogenic and “natural” influences on the quality of river water. T, EC, pH, TDS, NH₄, NO₃, NO₂, Turb., T.Hard., Ca, Mg, Na, K, Cl, SO₄, SiO₂ as physicochemical and TC, FC as biochemical variables have been analyzed in the water samples collected every month over a three-year period from 18 sampling stations along a 50 km section of Jajrood River that is under the influence of anthropogenic and natural changes. Exploratory analysis of experimental data has been carried out by means of PCA and CA in an attempt to discriminate sources of variation in water quality. PCA has allowed identification of a reduced number of mean 5 varifactors, pointing out 85% of both temporal and spatial changes. CA classified similar water quality stations and indicated Out-Meygoon as the most polluted one. Ahar, Baghgol, Rooteh, Befor Zaygan, Fasham, Roodak and Lashgarak were identified as affected by organic pollution. A Scree plot of stations in the first and second extracted components on PCA also gave us a classification of stations due to the similarity of pollution sources. CA and PCA led to similar results, though Out-Meygoon was identified as the most polluted station in both methods. Box-plots showed that PCA could approximately demonstrate temporal and spatial variations. CA gave us an overview of the problem and helped us to classify and better explain the PCA results.     

Assessment of the spring water quality in The Shoubak area,Jordan

The present study investigates the physical, chemical, and biological characteristics of spring water samples in Shoubak area in the southern Jordan. The samples were collected from May 2004 to May 2005. All samples were analyzed for temperature, conductivity, dissolved oxygen, pH, major cations (Ca²⁺, Mg²⁺, K⁺, Na⁺), major anions (Cl⁻, NO₃⁻, HCO₃⁻, SO₄²⁻, PO₄³⁻, F⁻), and trace metals (Fe²⁺, Al³⁺, Mn²⁺, Cu²⁺, Cr³⁺, Ni²⁺, Zn²⁺, Pb²⁺, Cd²⁺). Water quality for available springs showed high salinity through long period of contact with rocks. The ion concentrations in the water samples were from dissolution of carbonate rocks and ion exchange processes in clay. The general chemistry of water samples was typically of alkaline earth waters with prevailing bicarbonate chloride. Some springs showed elevated nitrate and sulfate contents which could reflect to percolation from septic tanks, cesspools, and agricultural practices. The infiltration of wastewater from cesspools and septic tanks into groundwater is considered the major source of water pollution. The results showed that there were great variations among the analyzed samples with respect to their physical, chemical and biological parameters, which lie below the maximum permissible levels of the Jordanian and WHO drinking water standards. The results indicate that the trace metals of spring’s water of Shoubak area do not generally pose any health or environmental problems. Factor analysis was used to identify the contributers to water quality. The first factor represents major contribution from anthropogenic activities, while the second one represents major contribution from natural processes.     

Nutrient transport through a Vegetative Filter Strip with subsurface drainage

The transport of nutrients and soil sediments in runoff has been recognized as a noteworthy environmental issue. Vegetative Filter Strips (VFS) have been used as one of the best management practices (BMPs) for retaining nutrients and sediments from surface runoff, thus preventing the pollutants from reaching receiving waters. However, the effectiveness of a VFS when combined with a subsurface drainage system has not been investigated previously. This study was undertaken to monitor the retention and transport of nutrients within a VFS that had a subsurface drainage system installed at a depth of 1.2 m below the soil surface. Nutrient concentrations of NO₃-N (Nitrate Nitrogen), PO₄⁻ (Orthophosphorus), and TP (Total Phosphorus) were measured in surface water samples (entering and leaving the VFS), and subsurface outflow. Soil samples were collected and analyzed for plant available Phosphorus (Bray P1) and NO₃-N concentrations. Results showed that PO₄⁻, NO₃-N, and TP concentrations decreased in surface flow through the VFS. Many surface outflow water samples from the VFS showed concentration reductions of as much as 75% for PO₄⁻ and 70% for TP. For subsurface outflow water samples through the drainage system, concentrations of PO₄⁻ and TP decreased but NO₃-N concentrations increased in comparison to concentrations in surface inflow samples. Soil samples that were collected from various depths in the VFS showed a minimal buildup of nutrients in the top soil profile but indicated a gradual buildup of nutrients at the depth of the subsurface drain. Results demonstrate that although a VFS can be very effective in reducing runoff and nutrients from surface flow, the presence of a subsurface drain underneath the VFS may not be environmentally beneficial. Such a combination may increase NO₃-N transport from the VFS, thus invalidating the purpose of the BMP.     

A COMPARISON OF RUNOFF QUALITY EFFECTS OF ORGANIC AND INORGANIC FERTILIZERS APPLIED TO FESCUEGRASS PLOTS1

ABSTRACT: Application of fertilizer can degrade quality of runoff, particularly during the first post-application, runoff-producing storm. This experiment assessed and compared runoff quality impacts of organic and inorganic fertilizer application for a single simulated storm occurring seven days following application. The organic fertilizers used were poultry (Gallus gallus domesticus) litter, poultry manure, and swine (Sus scrofa domesticus) manure. All fertilizers were applied at an application rate of 217.6 kg N/ha. Simulated rainfall was applied at 50 mm/h for an average duration of 0.8 h. Runoff samples were collected, composited, and analyzed for nitrate N (NO₃-N), ammonia N (NH₃-N), total Kjeldahl N (TKN), ortho-P (PO₄-P), total P (TP), chemical oxygen demand (COD), total suspended solids (TSS), fecal coliforms (FC), and fecal streptococci (FS). Application of the fertilizers did not alter the hydrologic characteristics of the receiving plots relative to the control plots. Concentrations of fertilizer constituents were almost always greater from treated than from control plots and were usually much greater. Flow-weighted mean concentrations of NH₃-N, PO₄-P, and TP were highest for the inorganic fertilizer treatment (42.0, 26.6, and 27.9 mg/L, respectively). Runoff COD and TSS concentrations were greatest for the poultry litter treatment. Concentrations of FC and FS were greater for fertilized than for control plots with no differences among fertilized plots, but FC concentrations for all treatments were in excess of Arkansas' primary and secondary contact standards. Mass losses of fertilizer constituents were low (≤ 3 kg/ha) and were small proportions (≤ 3 percent) of amounts applied.     

Growth and macronutrient removal of water hyacinth in a small secondary sewage treatment plant

Studies have been made of the growth characteristics of water hyacinth, Eichhornia crassipes (Mart.) Solms, and its ability to remove N, P and K, in a secondary settling pond of a small secondary sewage treatment plant serving both the academic and residential blocks of the Swire Marine Laboratory, University of Hong Kong. The treatment plant consists of, in series, a primary settling tank, a trickling filter compartment and a secondary settling pond from which part of the treated wastewater is recycled to the primary settling tank while the remaining effluent (1 to 2 m³ daily) mixes with and hence is diluted by the outflowing seawater from the aquarium system of the Swire Marine Laboratory before discharge to the sea. Samples of wastewater have been taken regularly from the primary sedimentation pond, the outflow of the trickling filter, the secondary settling pond and the effluent of the treatment plant (before mixing with aquarium outflow) since January, 1992. Physical, chemical and biological characteristics of the samples have been determined and are typical of secondary effluents, with a mean pH of about 7.5, total solids 1200 mg L⁻¹, suspended solids 45 mg L⁻¹, conductivity 2000 μS cm⁻¹, salinity 1 ppt, dissolved oxygen 2 mg L⁻¹, BOD₅ 45 mg L⁻¹, Kjeldahl-N 30 mg L⁻¹, NH₄,-N 25 mg L⁻¹, NO₃-N 4 mg L⁻¹, total P 10 mg L⁻¹, K 35 mg L⁻¹ and total coliforms of less than 10⁵ colonies 100 ml⁻¹.Water hyacinth plants have been stocked in the secondary settling pond as an integral part of the treatment plant so as to improve the quality of, as well as to retrieving and recycling nutrient elements from, the wastewater. The plants are periodically harvested to maintain an active growing crop. The growth rate, standing crop biomass, tissue nutrient composition, nutrient storage and accumulation rate of two growth cycles, one from February 25 to March 18 (mean temperature 17.6°C) and the other from 22 April to 12 May (24.8°C) are reported. The water hyacinth assumed a relatively high standing crop biomass of 10 kg m⁻² (5 to 6 t DM ha⁻¹), and growth rates of 48 and 225 g m⁻² day⁻¹, respectively, for the first and second growth period. Nutrient storage capacities were relatively high, at about 20, 7.5 and 16.5 g m⁻² for N, P and K, respectively. The nutrient composition was very high, reaching 5.42% for N, 1.97 for P, and 4.57 for K. Both the stem and lamina accumulated high levels of N, while the petiole had the highest level of P and K. Apart from nutrient removal, the water hyacinth also helped to decrease the suspended solids, BOD₅ value and total coliforms of the wastewater.It is concluded that water hyacinth improves the quality of wastewater in such small-scale sewage treatment plants and it is recommended that frequent harvests of water hyacinth would increase the treatment efficiency, especially during the active growing season with high temperatures coupled with intense solar radiation.     

Vegetation as an Indicator of Soil Properties and Water Quality in the Akarçay Stream (Turkey)

In this study, the relationship among water quality, soil properties, and plant coverage in the region of the Akarçay stream was examined. Correlation analyses were carried out between soil samples taken from each of four plant communities in the Akarçay basin and water in the Akarçay stream. The four plant communities in the study area are as follows: Limonium lilacinum (Boiss. et Bal.) Wag., Alhagi pseudalhagi (M. Bieb.) Desv. Peganum harmala L., and Hordeum marinum Huds. subsp. marinum. B, Cl, EC, K, Mg, Na, pH, and SO₄ data from both soil and water samples were subjected to statistical analysis, and significant correlations were obtained (p < 0.05). These correlations indicated that the chemical features of the soil had a major effect on water quality. The important parameters were B, Cl, EC, K, Mg, Na, pH, and SO₄ for Limonium lilacinum communities; Ca, K, and pV for Peganum harmala; and B, Cl, Mg, pH, and pV for Alhagi pseudalhagi. There were also statistically significant relationships (p < 0.05) among the parameters examined. These findings strongly suggested that these plant communities can be used as indicators for soil chemistry and water quality.     

Patterns of Streamwater Acidity in Lye Brook Wilderness,Vermont, USA

Under the United States Clean Air Act Amendments of 1977, a class I designation safeguards wilderness areas from the negative effects of new sources of air pollution. We monitored streamwater chemistry in the class I Lye Brook Wilderness in southwestern Vermont from May 1994 through August 1995. Stream samples were collected biweekly at nine sampling locations throughout the wilderness and were analyzed for major cations and anions, dissolved organic carbon, pH, and acid-neutralizing capacity. Eight of nine sites sampled had mean annual acid neutralizing capacity values below zero. During the study period, decreases in streamwater acid neutralizing capacity values were caused primarily by SO₄ ²⁻. At some sites, however, NO₃ ⁻ and naturally occurring, weak organic acids were seasonally important. During high discharge, the low pH and high concentrations of inorganic monomeric Al were at levels that are toxic to acid-sensitive aquatic species. Watershed mass balances were calculated to determine annual gains or losses for measured ions. These budgets indicate that S inputs and outputs were nearly equal, there was a net loss of base cations, and a net gain in N. How long these watersheds can continue to assimilate additional N inputs is unknown.     

Fertilizer Management in Watersheds of Two Ramsar Wetlands and Effects on Quality of Inflowing Water

Two field experiments were carried out in the watersheds of two Ramsar wetland areas, Lakes Koronia and Volvi (area A) and Lakes Mikri and Megali Prespa (area B), to study the effect of application of N fertilizer on wheat yields, the quality of runoff water, and the quality of stream water. The treatments were a combination of two methods of fertilizer application (total amount in fall, and 2/3 in fall + 1/3 in spring) at three rates (0, 100, and 200 kg N/ha) with four replications. Concentrations of NH₄ ⁺, NO₃ ⁻, NO₂ ⁻, P, and Cl⁻ and pH were determined in all water samples. Runoff water quality was not influenced by fertilizer application in either area. Chemical parameters for water did not differ along the selected watercourses in area B, while in area A they were higher in the samples taken near Lake Koronia than in the samples taken upstream, indicating that the watercourses are polluted downstream by nonagricultural sources. The differences in wheat yields between the 100 and 200 kg N/ha application rates were not high. These results call for better fertilizer management in order to achieve better yields and to diminish the possibility to have negative effects to the environment.     

BIOGEOCIIEMISTRY OF AN OLD-GROWTH FORESTED WATERSHED,OLYMPIC NATIONAL PARK,WASHINGTON1

ABSTRACT: The biogeochemistry of a coastal old-growth forested watershed in Olympic National Park, Washington, was examined. Objectives were to determine: (1) concentrations of major cations and anions and dissolved organic C (DOC) in precipitation, throughfall, stemflow, soil solution and the stream; (2) nutrient input/output budgets; and (3) nutrient retention mechanisms in the watershed. Stemilow was more acidic (pH 4.0–4.5) than throughfall (pH 5.1) and precipitation (pH 5.3). Organic acids were important contributors to acidity in throughfall and stemflow and tree species influenced pH. Soil solution pH averaged 6.2 at 40 cm depth. Stream pH was higher (7.6). Sodium (54.0 μeq L-¹) and Cl (57.6 μeq L^?1) were the dominant ions in precipitation, reflecting the close proximity to the ocean. Throughfall and stemflow were generally enriched in cations, especially K. Cation concentrations in soil solutions were generally less than those in stemilow. Ion concentrations increased in the stream. Dominant ions were Ca (759.7 μeq L^?1), Na (174.4 μeq L^?1), HCO₃ (592.0 μeq L^?1), and SO₄ (331.5 μeq L^?1) with seasonal peaks in the fall. Bedrock weathering strongly influenced stream chemistry. Highest average NO₃ concentrations were in the stream (5.2 μeq L^?1) with seasonal peaks in the fall and lowest concentrations in the growing season. Nitrogen losses were similar to inputs; annual inputs were 4.8 kg/ha (not including fixation) and stream losses were 7.1 kg/ha. Despite the age and successional status of the forest, plant uptake is an important N retention mechanism in this watershed.     

SEDIMENT AND NITROGEN TRANSPORT IN GRASS FILTER STRIPS1

ABSTRACT: An 18-month field experiment was conducted to evaluate the effectiveness of grass filter strips in removing sediment and various nitrogen species from runoff. Runoff was collected from six 3.7 m wide experimental plots with 24.7 m long runoff source areas. Two plots had 8.5 m filters, two plots had 4.3 m filters, and two plots had no filters. Runoff was analyzed for total suspended solids (TSS), total Kjeldahl nitrogen (TKN),. filtered TKN (FTKN), NH₄⁺-N, and NO₃-N. The Mann-Kendall nonparametric test for trend (changes in filter effectiveness over time) indicated that there were no trends in the yields and concentrations of TSS, NO₃^--N, NH₄-N, TKN, and FTKN for the 8.5 m filter over time. For the shorter 4.3 m filters, there were significant upward trends in TKN yield and downward trends in TSS, NH4-N, and FTKN concentrations, indicating that trapping efficiency may have started changing with time. The Kruskal-Wallis test indicated that the 8.5 m filters reduced median yields and concentrations of TSS and all N species, but the 4.3 m filters only reduced the median yields and concentrations of TSS, NH₄⁺-N, TKN, and the median concentration of FTKN. The 8.5 and 4.3 m filters reduced contaminate yields and concentrations from 42 to 90 percent and from 20 to 83 percent, respectively.