https://pubag.nal.usda.gov/download/10780/pdf

rosetta: a computer program for estimating soil hydraulic parameters with hierarchical pedotransfer functions

A method is presented for developing probability density functions for parameters of soil moisture relationships of capillary head [h(θ)] and hydraulic conductivity [K(θ)]. These soil moisture parameters are required for the assessment of water flow and solute transport in unsaturated media. The method employs a statistical multiple regression equation proposed in the literature for estimating [h(θ)] or [K(θ)] relationships using the soil saturated water content and the percentages of sand and clay. In the absence of known statistical distributions for either [h(θ)] or [K(θ)] relationships, the method facilitates modeling by providing variability estimates that can be used to examine the uncertainty associated with water flow or solute transport in unsaturated media.

Developing joint probability distributions of soil water retention characteristics

This report describes the RETC computer code for analyzing the soil water retention and hydraulic conductivity functions of unsaturated soils. These hydraulic properties are key parameters in any quantitative description of water flow into and through the unsaturated zone of soils. The program uses the parametric models of Brooks-Corey and van Genuchten to represent the soil water retention curve, and the theoretical pore-size distribution models of Mualem and Burdine to predict the unsaturated hydraulic conductivity function from observed soil water retention data. The report gives a detailed discussion of the different analytical expressions used for quantifying the soil water retention and hydraulic conductivity functions. A brief review is also given of the nonlinear least-squares parameter optimization method used for estimating the unknown coefficients in the hydraulic models. Several examples are presented to illustrate a variety of program options. The program may be used to predict the hydraulic conductivity from observed soil water retention data assuming that one observed conductivity value (not necessarily at saturation) is available. The program also permits one to fit analytical functions simultaneously to observed water retention and hydraulic conductivity data. The report serves as both a user manual and reference document. Detailed information is given on the computer program along with instructions for data input preparation and sample input and output files. A listing of the source code is also provided.

/pdf/the-retc-code-for-quantifying-the-hydraulic-functions-of-30xerlmq7o.pdf

The RETC code for quantifying the hydraulic functions of unsaturated soils

Summary
1. The thermal regime of rivers plays an important role in the overall health of aquatic ecosystems, including water quality issues and the distribution of aquatic species within the river environment. Consequently, for conducting environmental impact assessments as well as for effective fisheries management, it is important to understand the thermal behaviour of rivers and related heat exchange processes.

2. This study reviews the different river thermal processes responsible for water temperature variability on both the temporal (e.g. diel, daily, seasonal) and spatial scales, as well as providing information related to different water temperature models currently found in the literature.

3. Water temperature models are generally classified into three groups: regression, stochastic and deterministic models. Deterministic models employ an energy budget approach to predict river water temperature, whereas regression and stochastic models generally rely on air to water temperature relationships.

4. Water temperature variability can occur naturally or as a result of anthropogenic perturbations, such as thermal pollution, deforestation, flow modification and climate change. Literature information is provided on the thermal regime of rivers in relation to anthropogenic impacts and such information will contribute to the better protection of fish habitat and more efficient fisheries management.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2427.2006.01597.x

The thermal regime of rivers : a review

Soil physical quality: Part I. Theory, effects of soil texture, density, and organic matter, and effects on root growth

The Pesticide Root Zone Model (PRZM): A procedure for evaluating pesticide leaching threats to groundwater

To simulate stream temperatures on a watershed scale, shading dynamics of topography and ri­ parian vegetation must be computed for estimating the amount of solar radiation that is actually absorbed by water for each stream reach. A series of computational procedures identifying the geometric relationships among the sun position, stream location and orientation, and riparian shading characteristics were used to develop a computer program called SHADE. The SHADE-generated solar radiation data are used by the Hydrologic Simulation Program-FORTRAN (HSPF) to simulate hourly stream temperatures. A methodology for computing the heat flux between water and streambed was selected, evaluated, and implemented in the HSPF code. This work advances the state of the art in watershed analysis by providing a quantitative tool for relating riparian forest management to stream temperature, which is a vital component of aquatic habitat. This paper describes the modeling strategies, the SHADE program in terms of algorithms and procedures, the integration of SHADE with HSPF, and the algorithms and evaluation of the bed conduction of heat. A companion paper presents an application of the SHADE-HSPF modeling system for the Upper Grande Ronde watershed in northeast Oregon.

Stream Temperature Simulation of Forested Riparian Areas: I. Watershed-Scale Model Development

Three simplistic models are developed for evaluating the transport of organic pollutants through soil to ground water. The models consider mobility and first-order degradation. The first calculates linear sorption/desorption of the pollutant and first-order degradation without considering dispersion. The second is similar to the first but also considers dispersion. The third considers nonlinear sorption following a Freundlich equation and first-order degradation but does not consider dispersion. The models are compared to field data for the pesticides aldicarb and DDT. The models projected a lower mobility for DDT than was observed in the field.

Robert F. Carsel

Papers

Developing joint probability distributions of soil water retention characteristics

The Pesticide Root Zone Model (PRZM): A procedure for evaluating pesticide leaching threats to groundwater

Stream Temperature Simulation of Forested Riparian Areas: I. Watershed-Scale Model Development

Approximating Pollutant Transport to Ground Watera

Characterizing the uncertainty of pesticide leaching in agricultural soils