Modeling phosphorus in the environment - Chapter 13 pptx

... conductivity (continued) © 2007 by Taylor & Francis Group, LLC 306 Modeling Phosphorus in the Environment In addition to using the multiplicative approach, the Pennsylvania P Index varies the transport ... of the P Index, as illustrated by the Pennsylvania P Index (Table 13. 2 and Table 13. 3) (Weld et al. 2003). Included as an initial step in the Pennsylvania...

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... working on a modeling approach to BMP evaluation (see Chapter 15 on BMPs in this book; Gitau et al. 2001). An initial step in modeling BMP-induced reduction in P loss is the characterization of the ... overlying waters. In the short term, however, river flow and physical properties of the sediments will in uence the amount of sediment P leaving the watershed in th...

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... (g/ha) Oct-96 Mar-97 Sep-97 Mar-98 Sep-98 Mar-99 Sep-99 Mar-00 Sep-00 Time (months) 1200 1000 800 600 400 200 0 Observed Predicted Total P loss (g/ha) Oct-96 Mar-97 Sep-97 Mar-98 Sep-98 Mar-99 Sep-99 ... change in the input leads to a 1% relative change in the output. A negative value indicates that input and output are inversely related. The greater the absolute value of the in...

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... Modeling of Phosphorus 413 17.10 SUMMARY Much progress has been made in the modeling of P in the environment over the past 30 years. To continue this progress, the following improvements to modeling ... that measured in streams of the region. 17.7 PHOSPHORUS INDICES In the present authors’ opinion, P indices (PIs) can be considered a type of model representing...

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... rain falling during the time of concentration, R tc , was proportional to the amount of rain falling during the 24-h period, or where α tc is the fraction of daily rainfall that occurs during ... in ltration using the Green-Ampt or other in ltration equation and then to subtract in ltration from rainfall to determine the amount of runoff. The runoff hydrograph can then be d...

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... on the size and spacing of the drains (van der Ploeg et al. 1999). Models described in the following chapters simulate tile drain flow in a variety of ways, including the Richards equation linked with ... routines depicting P leaching in the soil profile. Recent interest in determining P leaching losses may lead to alternative methods for modeling P leaching. Simplified forms...

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... Novak et al. 2003). Phosphorus 124 Modeling Phosphorus in the Environment The concept of sediment EPC 0 might provide a useful mechanism to simulate in- stream processes in these watershed models. ... watershed, FD-36, detailed in Figure 5.1. The sediments were placed in the fluvarium to a 3-cm depth, and water was recir- culated over the sediment at a rate represen...

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... 134 Modeling Phosphorus in the Environment 6.3 UNCERTAINTY IS NOT ONLY STATISTICS The aim of science, however, is a single true description of reality. The ambiguity arising from uncertainties ... rejecting a model because of errors in the data. Thus, in the case of the grazing inputs and the imbalance in the hydrological fluxes, it is argued that the rejection...

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... NO 3 is the amount of nitrate in the soil layer (kg N ha −1 ). The C:P ratio is calculated as (7.14) 7.2.3 INORGANIC PHOSPHORUS SORPTION The inorganic P pool, originating either from mineralization ... Taylor & Francis Group, LLC 172 Modeling Phosphorus in the Environment the solution (labile) and active mineral pools is estimated using the following equi- libri...

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... was delineated into FIGURE 8.4 Upper Etowah River basin with the solid dot indicating the watershed outlet at Canton, Georgia. The gray lines indicate the stream network, and the dark lines indicate ... LLC 212 Modeling Phosphorus in the Environment modeling water movement in HSPF. Donigian and Love (2003) and U.S. Environ- mental Protection Agency (2006) are helpful...

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