Regonda, Satish K ¹ ; Rajagopalan, Balaji ² ; Clark, Martyn ³ ; Zagona, Edith ⁴

¹ Dept of Civil, Environmental & Architectural Engineering, Cooperative Institute for Research in Environmental Sciences, University of 欧美口爆视频 at Boulder
² Dept of Civil, Environmental & Architectural Engineering, Cooperative Institute for Research in Environmental Sciences, University of 欧美口爆视频 at Boulder
³ Cooperative Institute for Research in Environmental Sciences, University of 欧美口爆视频 at Boulder
⁴ Center for Advanced Decision Support for Water and Environmental Systems, University of 欧美口爆视频 at Boulder

We propose a multi-model ensemble forecast framework for streamflow forecasts at multiple locations that incorporates large-scale climate information. It has four broad steps - (i) Principal Component Analysis is performed on the spatial streamflows to identify the dominant modes of variability; (ii) Potential predictors of the dominant streamflow modes are identified from among large-scale climate features and snow water equivalent information; (iii) Objective criterion is used to select a suite of candidate nonlinear regression models each with different predictors and; (iv) Ensemble forecasts of the dominant streamflow modes are generated from the candidate models and are combined objectively to produce a multi-model ensemble 鈥� which are then back transformed to produce spatially coherent streamflow forecasts at all the locations. The utility of the framework is demonstrated in the skillful forecast of spring seasonal streamflows at six locations in the Gunnison River Basin at several lead times. The generated ensemble streamflow forecast provide valuable and useful information for optimal management and planning of water resources in the basin.

Regonda, S., B. Rajagopalan, M. Clark, and E. Zagona, 2005,A Multi-model Ensemble Forecast Framework: Application to Spring Seasonal Flows in the Gunnison River Basin , Water Resources Research, (accepted, pending revisions).

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Pontius, Frederick W. ¹

¹ Dept. of Civil, Environmental, and Architectural Engineering, University of 欧美口爆视频, Boulder, Colo.

Watershed control is one option within the US Environmental Protection Agency鈥檚 (USEPA鈥檚) Long-Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) microbial toolbox for public water systems to provide extra protection against Cryptosporidium. To receive credit for removal of Cryptosporidium, a watershed control program must meet certain requirements.

Watershed control programs must include an analysis of the system鈥檚 source water vulnerability to the different sources of Cryptosporidium. Assessments must include a characterization of watershed hydrology, identification of an 鈥渁rea of influence on source water quality,鈥� sources of Cryptosporidium, seasonal variability, and the relative impact of the sources of Cryptosporidium on the system鈥檚 source water quality. An analysis of sustainable interventions and an evaluation of their relative effectiveness in reducing Cryptosporidium in source water is required.

Federal regulatory policy can have both a positive and negative affect on the advancement of science. This review of the state of knowledge regarding Cryptosporidium sources, fate, and transport within a surface watershed demonstrates that USEPA鈥檚 presumptive 0.5 log removal 鈥榗redit鈥� has a weak scientific basis. The implications of this for researchers, regulators, and regulated water utilities will be discussed.

USEPA. 2006, Final Long Term 2 Enhanced Surface Water Treatment Rule. Federal Register, v. 71, p. 653-702.

Davies, C., Kaucner, C., Altavilla, N., Ashbolt, N., Fuerguson, C., Krogh, M., Hijnen, W., Medema, G., and Deere, D. 2005, Fate and Transport of Surface Water Pathogens in Watersheds, AWWA Research Foundation, Denver, Colo.

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Nordstrom, D. Kirk ¹

¹ U.S. Geological Survey, Boulder, CO

Research in chemistry, geochemistry, and hydrogeochemistry has been applied successfully to identify the geochemical processes that produce acid rock drainage and determine its fate, and to understand remediation scenarios. When iron in acid drainage fully oxidizes, does the pH always decrease? No, it can increase and chemistry and microbiology are keys to understanding the answer (1). What conditions cause efflorescent salts to form at mine sites? Water, drawn by capillary forces, evaporates to dryness and the efflorescent salts are left. In acid sulfate environments these salts usually form from waters of negative pH and very high metal concentrations (2). Can pH be negative? Not only can it be theoretically, but such low pH waters actually exist at Iron Mountain (2,3). Is mine plugging a reasonable option for treating acid mine drainage flowing from a portal? Probably not, unless you wish to increase the cost and complexity of the problem. Iron Mountain, California and Summitville, 欧美口爆视频 are good examples to prove that point (2). If several alternative remedial options are available with estimates for each of the decrease in loading, can the resultant improvement in stream water quality be predicted? Yes, by applying carefully controlled steady-injection tracer tests combined with synoptic sampling (4). Can ground-water quality before mining be estimated after mining has begun? The Questa project, New Mexico, is one of the first successful examples of this analysis.

(1) Nordstrom, D.K. Modeling low-temperature geochemical processes: in Drever, J.I., vol. ed., Vol. 5, Surface and Ground Water, Weathering and Soils, Treatise on Geochemistry, Holland, H.D. and Turekian, K.K., ex. eds., Elsevier, Amsterdam, 37-72, 2004.

(2) Nordstrom, D.K. and Alpers, C. N. Proc. Nat鈥檒. Acad. Sci. 96, (1999), 3455.

(3) Nordstrom, D.K., Alpers, C.N., Ptacek, C.J. and Blowes, D.W. Envir. Sci. Tech. 34, (2000) 254.

(4) Ball, J.W., Runkel, R.L., and Nordstrom, D.K. Chap. 3, In Environmental Sciences and Environmental Computing. Vol. II, P. Zanetti (ed.), the EnviroComp Institute, 2004, (http://www.envirocomp.org).

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Neupauer, Roseanna M ¹

¹ Univ. of 欧美口爆视频

Wavelet analysis is a relatively new tool for data analysis and signal processing. Similar to Fourier analysis, wavelet analysis identifies dominant periods or scales in one-dimensional and multi-dimensional data sets. The key difference between Fourier analysis and wavelet analysis is in the global vs. local nature of the analysis. In Fourier analysis, the dominant scales or periods are assumed to be global (i.e., they do not change with time or position), while wavelet analysis can extract different dominant periods or scales at different times or positions. In this talk, we will present an overview of wavelet analysis, and we will demonstrate its usefulness in analysis of hydrologic data.

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Nanus, Leora ¹ ; Williams, Mark W. ² ; Campbell, Donald H. ³

¹ University of 欧美口爆视频 Boulder
² University of 欧美口爆视频 Boulder
³ United States Geological Survey

Acidification of high-elevation lakes in the Western United States is of concern because of the storage and release of pollutants in snowmelt runoff combined with steep topography, granitic bedrock, and limited soils and biota. The sensitivity of 850 lakes to acidification from atmospheric deposition of nitrogen (N) and sulfur was estimated by relating water-quality and landscape attributes in Glacier National Park, Yellowstone National Park, Grand Teton National Park, Rocky Mountain National Park and Great Sand Dunes National Park and Preserve. Water-quality data measured during synoptic surveys (n=151) were used to calibrate statistical models of lake sensitivity. Landscape attributes for the lake basins were derived from GIS including topography, bedrock type, soil type, and vegetation type. Using multivariate logistic regression analysis, probability estimates were developed for acid-neutralizing capacity (ANC), and sensitive lakes were identified. In the case of N deposition, water-quality data included dual isotopes of d15N and d18O of nitrate. Water-quality data collected at 60 lakes during fall 2004 were used for cross-validation and 85% of lakes sampled were accurately identified by the model. Lakes exceeding 60% probability of having an ANC concentration less than 100 microequivalents per liter are located in Rocky Mountain and Grand Teton National Parks, at elevations above 2800m, and greater than 83% of the basin with low buffering capacity bedrock.

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Montandon, Laure ¹ ; Small, Eric E. ²

¹ 欧美口爆视频 Boulder
² 欧美口爆视频 Boulder

The green vegetation fraction (Fg) is an important climate and hydrologic model parameter. Common methods to calculate Fg, like the Gutman and Ignatov (GI) approach and its derived quadratic version, are simple mixing models between two NDVI end-members: bare soil NDVI (NDVIo) and full vegetation NDVI. A common assumption is that the soil NDVI is close to zero (0.04 in the GI model). However, the distribution of soil NDVIs computed from 2906 samples shows that soil NDVI is generally much larger (mean NDVI of soil=0.21) and is also highly variable (standard deviation=0.1).

We show that the underestimation of NDVIo yields overestimations of Fg that are greatest for lower NDVI values close to the soil NDVI. As a result, this problem is most severe in areas with sparse vegetation cover, such as semi-arid regions; for typical western U.S. values (NDVI<0.45), the error on Fg varies between 0.1 and 0.23. As the error on Fg estimation is the greatest for lower NDVI values, the underestimation of NDVIo yields to underestimation of the temporal variability of Fg in areas with seasonal vegetation. In addition, there is large uncertainty in the estimation of Fg due to the observed variability of soil NDVI values. The standard deviation on Fg estimates is the highest, i.e. 0.14, in areas where 0.3

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Molotch, Noah ¹

¹ University of 欧美口爆视频, Cooperative Institute for Research in Environmental Sciences CIRES

A spatially distributed snowmelt model was used to simulate pixel-specific daily snowmelt and snow water equivalent (SWE) over the Rio Grande headwaters (3,419 km2). Melt flux estimates were coupled with three different time-series of snow covered area (SCA) observations from the Landsat Enhanced Thematic Mapper (ETM+), the Advanced Very High Resolution Radiometer, and the Moderate Resolution Imaging Spectroradiometer (MODIS). Modeled melt flux for each pixel was integrated over the 2001 and 2002 snowmelt seasons to obtain estimates of maximum SWE accumulation. Evaluation of model performance using snow survey data collected at 7 different intensive study areas indicated that SWE was reasonably simulated using the MODIS SCA data. Multi-resolution comparisons revealed tradeoffs in accuracy associated with the relatively fine temporal resolution of MODIS (~ daily) versus the high spatial resolution of ETM+ (i.e. 30 m). As the first application of this modeling approach at the operations-scale (e.g. > 1000 km2), this work has implications for developing physically based water supply forecasts and for understanding spatially explicit hydrological / biogeochemical feedbacks.

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Miller, Matthew ¹ ; McKnight, Diane ² ; Cory, Rose ³ ; Williams, Mark ⁴ ;Runkel, Robert ⁵

¹ Department of Civil, Environmental, and Architectural Engineering, Institute of Arctic and Alpine Research, University of 欧美口爆视频
² Department of Civil, Environmental, and Architectural Engineering, Institute of Arctic and Alpine Research, University of 欧美口爆视频
³ Department of Civil, Environmental, and Architectural Engineering, Institute of Arctic and Alpine Research, University of 欧美口爆视频
⁴ Department of Geography, Institute of Arctic and Alpine Research, University of 欧美口爆视频
⁵ U.S. Geologic Survey, Denver, CO

The influence of hyporheic zone interactions on the redox state of humic substances and other redox active species in an alpine stream/wetland ecosystem was investigated. The specific goals of this study were as follows: (1) to examine the chemical differences in redox active species between the stream and wetland, (2) to quantify chemical changes caused by hyporheic exchange, and (3) to apply the results of a stream reach experiment to watershed scale processes. The information gained in response to these objectives suggests that hyporheic zone interaction influences the oxidation state of dissolved humic substances as well as other redox active species. Furthermore, these results suggest that hyporheic exchange at the stream reach scale is an important process in determining energy flow at the watershed scale.

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McCleskey, R. Blaine ¹ ; Nordstrom, D. Kirk ² ; Maest, Ann S. ³

¹ U.S. Geological Survey, Boulder, CO
² U.S. Geological Survey, Boulder, CO
³ Buka Environmental, Boulder, CO

Published literature on the time stability of water samples containing dissolved As(III/V) and preserved with a variety of reagents has shown contradictory results (1-3). The redox state of dissolved As is important to the interpretation of its toxicity, mobility, and geochemical transformations. Aqueous As redox species are affected by both biotic (4) and abiotic processes (5). Photo-catalyzed Fe(III) reduction can cause As(III) oxidation (6; fig. 1a). However, storing the sample in the dark prevents photochemical reactions and the presence of Fe(II) or SO₄inhibits (fig. 1b) the oxidation of As(III) by Fe(III). In our experience, completely oxidized Fe does not coexist with completely reduced As in natural water samples. Furthermore, natural water samples containing high concentrations of Fe(III) will contain either Fe(II), SO₄, or both. Consequently, As(III) oxidation reactions observed in the laboratory are not observed in natural samples. Figure 1c shows 5 water samples, preserved with HCl, that have a range of pH, Fe(II/III), As(III/V) and SO₄ concentrations that were monitored for their As(III/V) ratio for 5-19 months. No significant change in As(III) concentration could be detected in these samples. Any field collection procedure that filters out microorganisms, adds a reagent that prevents dissolved Fe and Mn oxidation and precipitation, and isolates the sample from solar radiation will preserve the As(III/V) ratio.

(1) Bednar, A.J., Garbarino, J.R., Ranville, J.F., Wildeman, T.R., Environ. Sci. Technol. 36 (2003) 2213.

(2) Hall, G.E.M., Pelchat, J.C., Gauthier, G., J. Anal. At. Spectrom. 14 (1999) 205.

(3) McCleskey, R.B., Nordstrom, D.K., and Maest, A.S., Appl. Geochem. 19 (2004) 995.

(4) Ahmann, D., Roberts, A.L., Krumholz, L.R., Morel, F.M.M., Nature 371 (1994) 750.

(5) Cherry, J.A., Shaikh, A.U., Tallman, D.E., Nicholson, R.V., J. Hydrol. 43 (1979) 373.

(6) Emett, M.T., Khoe, G.H., Water. Res. 35 (2001) 649.

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Mantilla, Ricardo ¹ ; Gupta, Vijay K ²

¹ Department of Civil, Environmental, and Architectural Engineering.
Cooperative Institute for Research in Environmental Sciences (CIRES).
University of 欧美口爆视频 at Boulder.
² Department of Civil, Environmental, and Architectural Engineering.
Cooperative Institute for Research in Environmental Sciences (CIRES).
University of 欧美口爆视频 at Boulder.

For over 30 years, observations have shown that power laws relate annual peak-flow quantiles to drainage basin area (Figure 1). However, little progress has been made to understand the underlying physical processes that produce these features. Following theoretical work by Gupta and others, we have formulated an alternative framework to address the problem of peak flows scaling. This new framework predicts that statistical scaling of peak flows occurs during individual rainfall-runoff events. Preliminary data analysis of peak flows during individual rainfall-runoff events in Walnut Gulch Basin in Arizona agrees with this result (Figure 2).

In order to study this framework in real basins, we redefine the concept of basin response. Traditionally, basin response to a rainfall event refers to the hydrograph at the outlet of the basin. We extend this concept to include the spatial structure of peak flows for all complete order streams. We use numerical simulations in the Walnut Gulch Basin in Arizona (150 km^2) to test how different assumptions about runoff dynamics for hillslopes and channels impact basin response to a rainfall event (Figure 3). We find that statistical scaling of simulated peak flows does not hold under unrealistic assumptions of runoff dynamics. This result suggests that a more comprehensive view of the basin response to rainfall events can yield better understanding of the physical mechanisms that produce floods.

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