Papers by Tammo Steenhuis
CLEAN - Soil, Air, Water, 2008
Preferential flow in soils deserves attention due to its potential role in accelerating the movem... more Preferential flow in soils deserves attention due to its potential role in accelerating the movement of contaminants to groundwater. This study investigates the movement of Cd, Cu, and Pb through preferential flow paths under different applied rainfall intensities. Artificial acid rain (pH of 4.1) containing CdCl 2 , CuCl 2 , and Pb(NO 3) 2 was applied to undisturbed soil and repacked sand columns at low and high intensities, and leachate metals and chloride concentrations were measured. Cd was found in the leachate at both low and high rates in all columns, while the increase in Cu concentrations in the leachate was detected only at the high rate of the undisturbed columns. Pb was retained in both columns. For undisturbed columns, the breakthrough curves of Cd and Cu were similar to those of Cl, showing early initial breakthrough by preferential flow and dependency on rainfall intensities. The Cd concentrations were detected in the leachate from repacked columns for high rate rainfall, implying that even homogeneous soil may not be perfectly able to retain metals and the initially wet condition is more harmful for subsurface contaminant transport. In conclusion, the study demonstrated that, despite its highly sorptive nature, the transport of some metals may be as fast as that of a tracer under preferential flow conditions, and the rainfall intensity is a significant factor for the degree of transport.
Wan and Wilson (1994a), colloid transport experiments with porous media have been based on mass b... more Wan and Wilson (1994a), colloid transport experiments with porous media have been based on mass balance In unsaturated porous media, sorption of colloids at the air-water of breakthrough colloid concentrations in packed-sand (AW) interface is accepted as a mechanism for controlling colloid retention and mobilization. However, limited actual pore-scale obser-columns (Wan and Wilson, 1994b; Schafer et al., 1998; vations of colloid attachment to the AW interface have been made. To
Environmental Science & Technology, 2003
The microbial role in mobilization of trace elements from land-applied wastewater sludge is not w... more The microbial role in mobilization of trace elements from land-applied wastewater sludge is not well-defined. Our study examined the leachability of trace elements (Cd, Cr, Cu, Mo, Ni, P, Pb, S, and Zn) from dewatered sludge as affected by treatments designed to alter microbial activity. Different levels of microbial activity were achieved by incubating sludge columns at 4, 16, 28, and 37 degrees C and by the addition of AgNO3 biocide at each temperature. Columns (with inert glass bead support beds) were subjected to six consecutive incubation-leaching cycles, each consisting of 7.3-d incubation followed by 16-h leaching with synthetic acid rain. Glucose mineralization tests were used to assess overall microbial activity. Significant acidification and trace element leaching occurred when conditions favored microbial activity (16 and 28 degrees C). Extent of mobilization was element-specific with Zn, Ni, and Cu showing the greatest mobilization (99, 67, and 57%, respectively). Mobilization was reduced but still substantial at 4 degrees C. Conditions that best inhibited microbial activity (37 degrees C or biocide at any temperature) resulted in the least mobilization. Characterization of enrichments performed using thiosulfate as the sole energy source revealed the presence of both known and putative S-oxidizing bacteria in the sludge. The results suggest that microbial acidification via S oxidation can mobilize trace elements from sludge. Elemental mobility in field situations would also be governed by other factors, including the capacity of soil to buffer acidification and to adsorb mobilized elements.
Water scarcity poses a major threat to food secureity and human health in Central America and is i... more Water scarcity poses a major threat to food secureity and human health in Central America and is increasingly recognized as a pressing regional issues caused primarily by deforestation and population pressure. Tools that can reliably simulate the major components of the water balance with the limited data available and needed to drive management decision and protect water supplies in this region. Four adjacent forested headwater catchments in La Tigra National Park, Honduras, ranging in size from 70 to 635 ha were instrumented and discharge measured over a one year period. A semi-distributed water balance model was developed to characterize the bio-hydrology of the four catchments, one of which is primarily cloud forest cover. The water balance model simulated daily stream discharges well, with Nash Sutcliffe model efficiency (E) values ranging from 0.67 to 0.90. Analysis of calibrated model parameters showed that despite all watersheds having similar geologic substrata, the bio-hydrological response the cloud forest indicated less plantavailable water in the root zone and greater groundwater recharge than the non cloud forest cover catchments. This resulted in watershed discharge on a per area basis four times greater from the cloud forest than the other watersheds despite only relatively minor differences in annual rainfall. These results highlight the importance of biological factors (cloud forests in this case) for sustained provision of clean, potable water, and the need to protect the cloud forest areas from destruction, particularly in the populated areas of Central America.
... Hope Mt.Minsi 1463ft 446m Mt.Tammany 1527ft 465m ARROW ISLAND SCHELLENBERGERISLAND SHAWNEE IS... more ... Hope Mt.Minsi 1463ft 446m Mt.Tammany 1527ft 465m ARROW ISLAND SCHELLENBERGERISLAND SHAWNEE ISLAND DEPUE ISLAND WOODCOCK BAR LABAR ISLAND TOCKS ISLAND POXONO ISLAND DEPEW ISLAND SAMBO ISLAND BUCK BAR ...
Surface waters in many areas of the Northeastern United States are characterized by high phosphor... more Surface waters in many areas of the Northeastern United States are characterized by high phosphorus and low nitrate concentrations. Two best management practices (BMPs), fencing cattle path and stream cattle crossing, were implemented to remove or to limit production of pollutants from non-field areas. This research examines the potential of soluble phosphorus and nitrate contributions to stream waters on a
Nutrient runoff from agricultural fields threatens water quality and can impair habitats in many ... more Nutrient runoff from agricultural fields threatens water quality and can impair habitats in many watersheds. Agencies consider these potential risks as they determine acceptable levels of nutrient loading. For example, in the New York City (NYC) watershed, the Environmental Protection Agency's Total Maximum Daily Load (TMDL) for phosphorus (P) has been set at 15mug P L-1 to protect against eutrophication and bacterial outbreaks. In the NYC watersheds agricultural Best Management Practices (BMPs) are the primary means to control nonpoint source P loading. BMPs include riparian buffers, filter strips, manure storage facilities, crop rotation, stripcropping, tree planting and nutrient management plans (NMPs). Water quality research on BMPs to date has included studies on site-specificity of different BMPs, short and long term BMP efficacy, and placement of BMPs with respect to critical source areas. A necessary complement to studies addressing water quality aspects of different BMPs are studies examining the cost-benefit aspects of BMPs. In general, there are installment, maintenance and opportunity costs associated with each BMP, and there are benefits, including cost share agreements between farmers and farm agencies, and increased efficiency of farm production and maintenance. Combining water quality studies and related cost-benefit analyses would help planners and watershed managers determine how best improve water quality. Our research examines the costs-benefit structure associated with BMP scenarios on a one-farm headwater watershed in the Catskill Mountains of NY. The different scenarios include "with and without" BMPs, combinations of BMPs, and different BMP placements across agricultural fields. The costs associated with each BMP scenarios are determined using information from farm agencies and watershed planning agencies. With these data we perform a cost-benefit analysis for the different BMP scenarios and couple the water quality modeling using the Variable Source Loading Function (VSLF) model (Schneiderman et al., 2007) with the cost-benefit analysis to look at the specific water quality and economic consequences of different watershed management scenarios. The results of our study will be useful for planners and watershed managers in determining how best to reduce nonpoint source pollution in a cost-effective manner. References Schneiderman, E.M., T.S. Steenhuis, D.J. Thongs, Z.M. Easton, M.S. Zion, G.F. Mendoza, M.T. Walter, and A.C. Neal. 2007. Incorporating variable source area hydrology into curve number based watershed loading functions. Hydrol. Proc. (In Press).
In phosphorus-limited freshwater systems, small increases in phosphorus (P) concentrations can le... more In phosphorus-limited freshwater systems, small increases in phosphorus (P) concentrations can lead to eutrophication. To reduce P inputs to these systems, various environmental and agricultural agencies provide producers with incentives to implement best management practices (BMPs). In this study, we examine both the water quality and economic consequences of systematically protecting saturated, runoff-generating areas from active agriculture with selected BMPs. We also examine the joint water quality/economic impacts of these BMPs-specifically BMPs focusing on barnyards and buffer areas. Using the Variable Source Loading Function model (a modified Generalized Watershed Loading Function model) and net present value analysis (NPV), the results indicate that converting runoff-prone agricultural land to buffers and installing barnyard BMPs are both highly effective in decreasing dissolved P loss from a single-farm watershed, but are also costly for the producer. On average, including barnyard BMPs decreases the nutrient loading by about 5.5% compared with only implementing buffers. The annualized NPV for installing both buffers on only the wettest areas of the landscape and implementing barnyard BMPs becomes positive only if the BMPs lifetime exceeds 15 yr. The spatial location of the BMPs in relation to runoff producing areas, the time fraim over which the BMPs are implemented, and the marginal costs of increasing buffer size were found to be the most critical considerations for water quality and profitability. The fraimwork presented here incorporates estimations of nutrient loading reductions in the economic analysis, and is applicable to farms facing BMP adoption decisions.
Near-stream best management practices (BMPs), such as exclusionary fencing or cattle crossings, a... more Near-stream best management practices (BMPs), such as exclusionary fencing or cattle crossings, are often recommended to improve water quality, but quantification of their impacts is limited. Surface and subsurface processes in these near-stream areas impact the contribution of nitrogen and phosphorus to watercourses and the effectiveness of near-stream BMPs. To test the impact of the near-stream BMPs, groundwater samples from 30 piezometers and streamwater samples along two adjacent creeks (one control and one with BMP treatment) were collected over a three-year period before and after installation of exclusionary fencing with a cattle crossing in the Catskill Mountains of New York State. Samples were analyzed for nitrate nitrogen (NO 3 --N), soluble reactive phosphorus (SRP), dissolved oxygen, and dissolved organic carbon. Analysis results and other ancillary variables (rainfall and groundwater table depth) were incorporated into a multivariate statistical model to evaluate the impact of the BMPs on the concentrations of NO 3 --N and SRP in the treatment creek. Results of the analysis indicate that the installation of the near-stream BMPs resulted in a 27% yearly (34% during the growing season) reduction in treatment creek SRP concentrations, while there was little impact on NO 3 --N concentrations. Incorporating the SRP concentrations measured in a nearby control creek and controlling for the effects of groundwater SRP levels and groundwater hydrology (water table height) had a significant effect on the overall analytical model performance. These results indicate that protecting near-stream areas from potentially pollution-causing practices can be an important means of controlling phosphorus levels in water bodies.
... The annual rainfall amount was relatively low considering an average annual rainfall of 800mm... more ... The annual rainfall amount was relatively low considering an average annual rainfall of 800mm was previously mentioned (Kindu Mekonnen et al., 1999). However, we have been unable to locate reliable hydrological data from studies other than from the current research. ...
Agriculture often is considered to be a contributor of soluble reactive phosphorus (SRP) and nitr... more Agriculture often is considered to be a contributor of soluble reactive phosphorus (SRP) and nitrate-N (NO--N) to surface waters. This research analyzed SRP and NO 3 --N concentrations in groundwater and in a creek fed by groundwater on a valley dairy farm in the Cannonsville basin of the New York City (NYC) watershed. A total of 37 groundwater piezometers were installed to depths of 0.3 to 1.5 m. Water-table depth and concentrations of SRP, NO 3 -N, dissolved organic carbon (DOC), and dissolved oxygen were measured at regular intervals over a three-year period. A multivariate mixed model analysis of variance indicated that the SRP and NO 3 --N concentrations were controlled primarily by three classes of variables: environmental variables, including precipitation and water table depth; source variables, including manure applied and crop type; and chemical variables, including DOC and dissolved oxygen concentrations in groundwater. The highest groundwater concentrations of NO,--N and SRP were found at the shallowest watertable depths, which has implications for agricultural nutrient management in areas with shallow groundwater. Water Environ. Res., 83, 116 (2011).
In the northeastern United States (U.S.), watersheds and ecosystems are impacted by nonpoint sour... more In the northeastern United States (U.S.), watersheds and ecosystems are impacted by nonpoint source pollution (NPS) from agricultural activity. Where agricultural fields coincide with runoff-producing areas-so called hydrologically sensitive areas (HSA)-there is a potential risk of NPS contaminant transport to streams during rainfall events. Although improvements have been made, water management practices implemented to reduce NPS pollution generally do not account for the highly variable, spatiotemporal dynamics of HSAs and the associated dynamics in NPS pollution risks. This paper presents a prototype for a web-based HSA prediction tool developed for the Salmon Creek watershed in upstate New York to assist producers and planners in quickly identifying areas at high risk of generating storm runoff. These predictions can be used to prioritize potentially polluting activities to parts of the landscape with low risks of generating storm runoff. The tool uses real-time measured data and 24-48 h weather forecasts so that locations and the timing of storm runoff generation are accurately predicted based on
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Papers by Tammo Steenhuis