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Chief Seattle, 1854

Chief Seattle, 1854. Man did not weave the web of life: he is merely a strand of it. Whatever he does to the web, he does to himself. Use of the Water, Energy, and Biogeochemical Model (WEBMOD) to Simulate Water Quality at Five U.S. Geological Survey Research Watersheds.

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Chief Seattle, 1854

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  1. Chief Seattle, 1854 Man did not weave the web of life: he is merely a strand of it. Whatever he does to the web, he does to himself.

  2. Use of the Water, Energy, and Biogeochemical Model (WEBMOD) to Simulate Water Quality at Five U.S. Geological Survey Research Watersheds Rick Webb and fellow WEBBsters

  3. Relations between hydrology and solute fluxes at the five Water, Energy, and Biogeochemical Budget (WEBB) watersheds of the United States Geological Survey Rick Webb and fellow WEBBsters

  4. WEBB, XTOP_PRMS, and Net Solute Fluxes • What questions should WEBMOD be able to answer? • Five Principal Components • What does diametrically opposed mean anyway? • WEBMOD = XTOP_PRMS + PHREEQC • But will it be able to pick the best restaurant for Wednesday lunch?

  5. WEBB, XTOP_PRMS, and Net Solute Fluxes • What questions should WEBMOD be able to answer? • Five Principal Components • What does diametrically opposed mean anyway? • WEBMOD = XTOP_PRMS + PHREEQC • But will it be able to pick the best restaurant for Wednesday lunch?

  6. Trout Lake, Wisconsin Sleepers River, Vermont Panola Mountain, Georgia Loch Vale, Colorado Luquillo, Puerto Rico

  7. Loch Vale • Alpine /Subalpine ecosystem • Distinctions • 1 km of relief • 70% rock and talus • Ponds are wide spots on drainage • Very young soils

  8. Trout Lake (Allequash Creek) • Northern Temperate Lakes – Snow/GW system. • Distinctions • Sand box • Lakes and wetlands • Beaver dams • Limnology Center

  9. Sleepers River • Snowmelt dominated • Distinctions • History of watershed studies. • CRREL • Freeze-thaw studies • Includes different land uses.

  10. Panola Mountain • Secondary Forest • Distinctions • Granite outcrop • Variable subsurface and geology • Detailed hillslope data • Disconnected hillslope drainage after dry periods

  11. Luquillo Experimental Forest(Icacos Watershed) • Lower montane tropical rain forest • Distinctions • Ultisols with preferential flow paths (macropore and along regolith) • Hortonian overflow • Mass wasting • Cloud interception offset by Canopy evaporation • Tightly cycled nutrients

  12. Water, Energy, and Biogeochemical Budget Inputs - Outputs = Change in storage • Inputs • Incident radiation and ground heat flux • Precipitation with aerosols • Cloud interception • Regional ground water flow • Atmospheric aerosols and gases • Outputs • Sensible and latent heat • Runoff • Regional ground water flow • Inorganic mass and solutes • Biomass and organic matter Storage Bedrock, Snowpack Soil moisture, Surface water Ground water, Biomass, Soils • Hypothesis: The residence times and biogeochemical processes active along the various flow paths will determine the quality of surface and ground water in the watershed.

  13. Energy Net Radiation – Soil Heat Flux – D Storage = Sensible + Latent Heat

  14. (Precipitation) (Stream)

  15. PRMS+NWS Snow-17 + TOPMODEL = XTOP_PRMS

  16. Water fluxes in TOPMODEL

  17. Ksat(z) 0 0.1 0.2 0.3 0.4 0.5 0 0.2 m values (SZM) 5.00 0.4 2.50 1.70 0.6 1.00 Depth (z), in meters 0.50 0.25 0.8 0.17 0.10 1 1.2 1.4

  18. Field Capacity root zone Index Wilting Point Saturation Deficit SD(+) Land Surface Average water table Index exfiltrated Saturation water root Surplus zone SD(-) Average Saturation Deficit SBAR b) Increasing topographic index, ln(a/tan srz srmax Topographic index 1 2 3 4 5 6 7

  19. WEBMOD

  20. For each subcatchment For each topographic index

  21. 20 Basin Discharge Observed Simulated 10 DISCHARGE, IN CUBIC FEET PER SECOND 0 6 7 8 MARCH 1996 Panola Mountain – Basin discharge

  22. 20 Basin Valley Outcrop 10 DISCHARGE, IN CUBIC FEET PER SECOND 0 6 7 8 MARCH 1996 Panola Mountain – Basin, valley, and outcrop discharge

  23. 20 Valley Flows Total Macropore Baseflow Overland flow 10 DISCHARGE, IN CUBIC FEET PER SECOND 0 6 7 8 MARCH 1996 Panola Mountain – Flow generation in valley area

  24. 20 Basin Valley Outcrop 10 DISCHARGE, IN CUBIC FEET PER SECOND 0 6 7 8 MARCH 1996 Panola Mountain – Basin, valley, and outcrop discharge

  25. 20 Outcrop Flows Total Macropore Baseflow Overland flow Infiltration excess Saturated overland flow 10 DISCHARGE, IN CUBIC FEET PER SECOND 0 6 7 8 MARCH 1996 Panola Mountain – Flow generation in outcrop area

  26. Evapotranspiration Overland Flow Macropore flow Baseflow and exfiltration Average monthly flux, in centimeters 8 2 5 8 2 9 3 6 9 4 7 1 2 4 5 7 6 9 1 3 5 6 8 7 1 3 6 9 6 7 4 7 2 4 5 2 5 3 9 1 3 4 1 8 8 11 11 12 10 12 10 12 10 11 11 11 12 12 10 10 Allequash Icacos Loch Vale Panola Sleepers

  27. Hydrologic Variables • Net precipitation • Snowmelt • Actual evapotranspiration • Overland flow from infiltration-excess • Saturated overland flow • Root zone moisture • Flux of water from the saturated zone to the root zone • Macropore flow • Baseflow and exfiltration

  28. Base Cations Base Cations 2+ 2+ Ca Ca Mg Mg 2+ 2+ K K + + + + Na Na - - 2 2 - - 2 2 - - - - - - HCO HCO CO CO SO SO Cl Cl NO NO 3 3 3 3 4 4 3 3 Alkalinity Alkalinity Acid Anions Acid Anions Solutes • Cations H+, Ca2+, Mg2+, Na+, K+, NH4+ • Anions HCO3-, Cl-, SO42-, NO3- • and silica H4SiO4

  29. WEBB, XTOP_PRMS, and Net Solute Fluxes • What questions should WEBMOD be able to answer? • Five Principal Components • What does diametrically opposed mean anyway? • WEBMOD = XTOP_PRMS + PHREEQC • But will it be able to pick the best restaurant for Wednesday lunch?

  30. Principal Component Analysis (PCA) is a linear dimensionality reduction technique. Read “Reduce the number of variables needed to explain the data”

  31. Component 1 (50 percent of variance): 10 8 6 Allequash Andrews 4 Icacos 2 Panola Sleepers 0 -2 -4 1 2 3 4 5 6 7 8 9 10 11 12 Month

  32. Component 1 – Wet/Dry(+) Deluge/Melt(-) Drought/Freeze(50 percent of variance) • Accumulated solutes are flushed from the watershed by snow melt or alternately retained when precipitation and solutes are locked up when the basin freezes.

  33. Active system

  34. Base flow

  35. Component 2(+) Dry periods with cool, wet soils(-) Wet periods with warm soils with available root zone storage(14 percent of variance) • Retention of ammonia, nitrate, and sulfate is less during dry and cool periods with saturated soils than it is during wet warm periods with available root zone storage.

  36. Component 3(+) Dry soils during warm, dry periods(-) Wet soils during cool, wet periods(8 percent of variance) • This component describes the upward flux of water from the saturated zone into drying riparian soils during periods of high evapotranspiration. Exfiltration through desiccating surfaces increases the net export of nitrate and chloride; during wet and cool periods, the nitrate and chloride in the precipitation may move from the base of wet soils down to mix with ground water as might occur during ground water ridging.

  37. Component 4(+) Low base flows with limited recharge (-) Moderate baseflows with some recharge(7 percent of variance) • During very low flows, ions from deep in the soil profile are released; nutrients and sulfate are tightly retained near the surface. During moderate recharge events the nutrients and sulfate exports are rinsed into a more saturated soil profile to be released in the base flow as the contribution of base cations diminishes.

  38. Component 5(+) Spring melts or rains on dry soils(-) Late summer rains on wet soils(4 percent of variance) • Ammonia is taken up by growing vegetation in the spring. Mineralization of organic debris reintroduces the ammonia into the system to be released during late summer rains when transpiration begins shutting down.

  39. Late summer rains on wet soils, less NH4 retention 4% Melt on dry soils, NH4 retention -5 5 Base flows, increased wx products, Decrease nutrients and SO4 Recharge , decr. wx products, Increased nutrients and SO4 7% -4 4 Dry, warm periods, increased export of Cl and NO3 Wet, cool periods. Less export of Cl and NO3 8% -3 3 Wet, warm, retention of nutrients and sulfate. Dry, cool, less retention on nutrients and sulfate 14% -2 2 Drought/Freeze. Everything Retained Deluge/Melt. Everything exported. 50% -1 1 Dominant Component by Month and Year Variance Allequash Loch Vale Luquillo Panola Sleepers Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Month 92 93 94 95 96 97 92 93 94 95 96 97 92 93 94 95 96 97 92 93 94 95 96 97 92 93 94 95 96 97 Water Years 1992-1997

  40. Fall rain releases NH4 Melt on dry soil; NH4 retained Recharge; Dilute wx, nuts exp. Low flow; Wx export, nuts ret. Wet, cool; NO3, Cl retained Dry, warm; NO3, Cl exported Dry,cool; Nutrients exported Wet, warm; nutrients assim. Dry/Freeze; Solutes retained Storm/Melt; Solutes exported 25 Panola Mountain, GA 20 Allequash Creek, WI 15 10 5 0 25 Loch Vale, CO 20 Luquillo, PR 15 Component Score 10 5 0 25 Oct-93 Apr-94 Oct-94 Apr-95 Oct-95 Apr-96 Component Legend Sleepers River, VT 20 15 10 5 0 Oct-93 Apr-94 Oct-94 Apr-95 Oct-95 Apr-96

  41. WEBB, XTOP_PRMS, and Net Solute Fluxes • What questions should WEBMOD be able to answer? • Five Principal Components • What does diametrically opposed mean anyway? • WEBMOD = XTOP_PRMS + PHREEQC • But will it be able to pick the best restaurant for Wednesday lunch?

  42. WEBMOD • Modifications to XTOP_PRMS to enable forward feeding series of batch reactors: • Soil properties • Porosity, field capacity, wilting point, rooting depth, depth to bedrock, log-normal distribution of vertical hydraulic conductivity. • Explicit flow paths • Throughfall, transpiration, deep preferential flow • Track solute fluxes and storage • Couple with PHREEQC to enable geochemical simulations

  43. PHREEQC Capabilities • Aqueous, mineral, gas, surface, ion-exchange, and solid-solution equilibria • Kinetic reactions • 1D diffusion or advection and dispersion with dual-porosity medium • A powerful inverse modeling capability allows identification of reactions that account for the chemical evolution in observed water compositions • Extensive geochemical databases

  44. Implications for Watershed Management • WEBMOD will • aid in understanding the seasonality of water quantity and quality in watersheds in diverse hydroclimatic settings, and • provide estimates of antecedent and forecasted watershed hydrology and climatology to optimize water use and water quality for any given period

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