Journal of Hydrologic Engineering

Cross-sectional models, which represent two-dimensional flow in the vertical plane, tend to have problematic aspect ratios since the aquifer thickness is often small compared to the lateral extent of the flow domain. For that reason, the model domain is usually limited to the immediate area of interest, for instance the aquifer section underneath a dam. We propose a Cauchy boundary condition to represent flow from remote wetlands that are left out of the truncated model. The resistance to flow inherent to such a boundary depends on the aquifer properties and the resistance to flow through the wetland bottom. While the Cauchy boundary condition is based on the Dupuit-Forchheimer approximation to flow underneath the remote wetlands, the error appears to be negligible (less than 0.6%) for most practical cases, including flow in stratified aquifers. For the case of multiple aquifers underneath the wetlands, the total flow in the truncated model can be a few percent in error, which is typically acceptable for most engineering applications. The approach is illustrated with an application near a levee-borrow canal setting in the Florida Everglades.

An attempt has been made on modeling evaporative water loss from the on-farm reservoir (OFR) with biological shading in rainfed upland areas. Biological shading over the water surface of a lined OFR has been developed by growing a creeper, namely, bottle gourd (Lagenaria siceraria) on an erected bamboo platform. Based on normalized reference crop evapotranspiration, a canopy growth model was developed for predicting the percentage of ground cover of the creeper $\left(G_i\right)$ with respect to time. The predicted and observed $G_i$ values were in close agreement with each other having root-mean-square error (RMSE) of 11.43 and 5.86% during 2006 and 2007, respectively. The same model, when applied for simulating the growth rate of canopy cover on the embankment as well as on the bamboo platform of the OFR, maintained a very close agreement with the observed canopy cover on the embankment $\left(\text{RMSE}=\mathrm{0.79\%}\right)$ , whereas in case of bamboo platform the RMSE was 17.32 and 7.16% of observed canopy cover during 2006 and 2007, respectively. The radiation interception model developed by Hernandez-Suarez was modified to simulate the percentage of radiation interception $\left(R_i\right)$ with respect to the water surface of the OFR lying under the canopy cover. An evaporative water loss $\left(E_{\text{loss}}\right)$ model was developed for the creeper covered OFR using the fraction of radiation and heat energy not intercepted and the evaporation equation of the open OFR. The RMSE values for observed versus predicted $E_{\text{loss}}$ from the creeper covered OFR were 0.043 and $0.038{\text{m}}^3{\text{day}}^{-1}$ in 2006 and 2007, respectively. Saving of $E_{\text{loss}}$ due to biological shading up to 50% in comparison to the open OFR strongly supports the efficacy of the technology to mitigate $E_{\text{loss}}$ from the OFRs in rainfed areas.

This paper applies a stochastic inverse method, named as gradual conditioning (GC) method, to the fractured site of Äspö, Sweden, which is an underground hard rock laboratory initially designed as a potential future deep geological repository for spent nuclear fuel. The aim of this paper is (1) the verification of GC method in a real three-dimensional (3D) fractured rock medium, showing that the GC method is a competitive stochastic tool in highly heterogeneous aquifers, furthermore, it gathers a set of capabilities so far not included in any existing method; (2) to characterize the site as adequately as possible, experimental data are reproduced closely; (3) to provide measures on the uncertainty of the estimates by means of using multiple equally likely realizations, thus showing the importance of conditioning to as much information as possible in order to reduce the uncertainty; (4) to prove that this fractured media can be adequately modeled by assuming a (pseudo-) continuum media, or equivalent porous medium, in which fractures are represented by the introduction of discretization blocks of very high effective hydraulic conductivity $\left(K\right)$ ; (5) to describe how to take advantage of the available geological information and how to properly integrate this secondary data in the GC method; (6) to efficiently model the statistical distribution of the hydraulic conductivity data by using the concept of multiple statistical populations (SPs); each fracture plane and the rock matrix represent an independent SP; and (7) to highlight that the GC method is able to deal with nonmulti-Gaussian distributions, thus allowing to reproduce existing preferential flow channels, and therefore, to obtain lower (safer) radionuclide travel times from the deep geological repository to the biosphere.

The Upper Green River represents a vital water supply for southwestern Wyoming and Upper/Lower Colorado River Compact states. Rapid development in the southwestern United States combined with the recent drought has greatly stressed the water supply of the Colorado River system, and concurrently increased the interest in long-term variations in streamflow. The current research developed six new tree-ring chronologies in and adjacent to the Upper Green River Basin (UGRB). Nine proxy reconstructions (three main-stem streams and six headwater streams) of UGRB streamflow were created by combining these new tree-ring chronologies with existing tree-ring chronologies from sites adjacent to the UGRB. All UGRB streamflow reconstructions extended back to the year 1615 or earlier. The variance explained $\left(r^2\right)$ by these reconstructions ranged from a low of 0.44 at one headwaters gauge to 0.65 for the lowest main-stem gauge in the drainage. An extended reconstruction of the main-stem Green River gauge near Greendale, Utah extends back to 1439. As a group, the nine reconstructions show that strong regional coherency in interannual flow variability and multiyear to decadal flow regimes are consistent features of the preinstrumental period. Focusing on the Green River at Greendale reconstruction, our analyses point to unusual wetness in the 20th century and a regional hydroclimate characterized by inherent nonstationarity. Overall, these results suggest that instrumental records capture a relatively small subset of potential streamflow variability in the UGRB.

A physically based distributed hydrological model is coupled with an optimization algorithm for joint dam operation to reduce the flood peaks downstream. The decision variables are the release-inflow ratios. The heuristic algorithm seeds different release scenarios attempting to find the most suitable combination. The objective is to reduce the flood peak downstream, and the objective function is to minimize the difference between the simulated and threshold discharges. The latter depends on the purpose of flood management at the basin. Here, it is proposed as the mean discharge during heavy rainfall and is used to start a special dam operation. In order to fulfill the objective function, the reservoirs are expected to release water before the flood event takes place and close the gates during the flood peaks to replenish the released water beforehand. The developed system was applied to the upper Tone River in Japan where the optimal release schedule from two key dams was obtained. The observed weather radar products were input to the hydrological model to simulate the discharge within the river network. Then, the simulated inflows were input to the dam storage functions. The release is routed downstream and the river discharge is evaluated at the control point. The results indicate that the proposed integrated operation can effectively reduce a flood peak suggesting the feasibility of real-time operation in future developments.