Silvio José Gumière

Bayesian Uncertainty Analysis of the Distributed Hydrological Model HYDROTEL

AbstractIn this study, a Bayesian, inference-based, Markov chain Monte Carlo (MCMC) method coupled with an autoregressive moving average (ARMA) error model framework was used to assess the uncertainty of the process-based, continuous, distributed hydrological model HYDROTEL when simulating daily streamflows. The uncertainty analysis was performed, as a case study, in two distinct watersheds (Montmorency, Quebec, Canada, and Sassandra, Ivory Coast, West Africa). The MCMC uncertainty analysis showed to be effective, primarily with respect to the fulfillment of the statistical assumptions of the error model. The results of the uncertainty analyses demonstrated that almost 95% of the observed daily outlet flows were bracketed by the 95% prediction uncertainty bands. This indicates that the parameter uncertainty associated with the ARMA error model could reach the prediction uncertainty. It was possible to mimic the prediction uncertainty using only the most sensitive model parameters for the Montmorency and S...

Modeling the effects of agricultural BMPs on sediments, nutrients, and water quality of the Beaurivage River watershed (Quebec, Canada)

Agriculture has evolved into the largest non-point source of surface water pollution in Canada as a result of intensification over the past forty years. The Canadian WEBs project (Watershed Evaluation of Beneficial Management Practices, BMPs) was launched to evaluate the environmental and economic performance of BMPs as a means to mitigate agricultural sediment and nutrient issues. In this paper, the Gestion Intégrée des Bassins versant à l’aide d’un Système Informatisé (GIBSI) (or Integrated Watershed Management using a Computer System) integrated modeling framework was used to evaluate the effects of different BMPs on sediment and nutrient yields, as well as water quality in the Beaurivage River watershed in the province of Quebec. A reference scenario was developed that describes the current situation (i.e., base case scenario) of the watershed by calibrating the models used within GIBSI, namely HYDROTEL for hydrology, the Revised Universal Soil Loss Equation (RUSLE) for soil erosion, the Erosion-the Productivity Impact Calculator (EPIC) of the Soil and Water Assessment Tool (SWAT) for contaminant transport and fate, and QUAL2E for stream water quality. The effects of four BMPs were studied: (1) vegetated riparian buffer strips, (2) precision slurry application, (3) grassland conversion of cereal and corn fields, and (4) no-till (on corn fields). Simulation results indicate that BMPs can be effective in reducing nutrient and suspended sediment loads in both surface runoff and stream flow. More specifically, buffer strip and crop rotation showed better efficiency than hog-slurry management and no-till on corn BMPs. Moreover, results highlight the need for further investigation of sediment dynamics in the stream network as well as in the riparian buffer strips.

Development of VFDM: a riparian vegetated filter dimensioning model for agricultural watersheds.

Dimensioning and positioning structural beneficial management practices (BMPs) represent a “real life” challenge for soil conservation engineers, managers, planners and policy-makers. Different factors, such as trapping efficiency; implementation, management, and opportunity costs (resulting from cropland loss), and government policies and guidelines need to be weighed to meet this challenge. The trapping efficiency of structural BMPs may depend on many parameters, including: (1) characteristics of vegetated filters (VF) such as width and slope, vegetation height, vegetation density and species composition, (2) flow characteristics such as runoff velocity, discharge volume and water height, and (3) sediment characteristics such as particle size, aggregation and concentration. Government policies and guidelines may include dimension and location of VFs and/or a cropland percentage that needs to be converted into VF areas. The main objectives of this paper are to: (1) describe the development of the Vegetated Filter Dimensioning Model (VFDM), a mathematical model to determine the optimal dimensions of riparian vegetated filter strips (RVFSs) in agricultural watersheds, and (2) illustrate the potential use of the model on a pilot watershed, the Beaurivage watershed, in Quebec, Canada. The latter was done for the sole purpose of model testing with readily available input parameters and data. The model calculates the optimal width with respect to vegetation, topographical, hydrological and sedimentological characteristics. The results of this case study showed that the average recommended RVFS for the Beaurivage River watershed is about 3 m wide. Le dimensionnement et le positionnement de bandes riveraines (BR) représentent un défi important pour les ingénieurs, gestionnaires, planificateurs et les représentants politiques qui décident des régulations dans ce domaine. Plusieurs facteurs, tel que l’efficacité de captation des sédiments; l’implémentation, la gestion et les coûts d’opportunité (résultant de la perte de terres agricoles), et les politiques et régulations gouvernementales doivent être pris en compte pour relever ce défi. L’efficacité de captation dépend de plusieurs paramètres, incluant (1) les caractéristiques de la BR, tel que sa largeur et sa pente, la hauteur de la végétation, la densité de végétation et les espèces en présence; (2) les caractéristiques de l’écoulement, tel que la vitesse de ruissellement, le volume d’écoulement et la hauteur d’eau, et (3) les caractéristiques des sédiments, tel que la taille des particules, leur agrégation et leur concentration. Les politiques et régulations gouvernementales peuvent inclure la dimension et l’emplacement des BR et/ou un pourcentage de terres agricoles devant être converties en BR. Les objectifs principaux de cet article sont : (1) décrire le développement de VFDM (Vegetated Filter Dimensioning Model), un modèle mathématique pour déterminer les dimensions optimales des bandes riveraines dans des bassins versants agricoles, et (2) illustrer l’utilisation potentielle du modèle sur un bassin versant pilote, le bassin de la rivière Beaurivage, Québec, Canada. Ce dernier objectif a été fait dans le but de tester le modèle avec des paramètres et données d’entrées déjà disponibles. Le modèle calcule la largeur optimale en fonction des caractéristiques topographiques, hydrologiques, sédimentologiques et de la végétation. Les résultats de cette étude indiquent que les largeurs des bandes riveraines dans le bassin de la rivière Beaurivage devraient être de l’ordre de 3 m.

Evaluating the Impact of the Spatial Distribution of Land Management Practices on Water Erosion: Case Study of a Mediterranean Catchment

Abstract: The spatial distribution of land management practices (LMPs), such as the use of vegetated filters, may have a strong impact on their efficiency in trapping sediments and pollutants. Distributed water erosion models help managers, planners, and policymakers optimize the efficiency of these LMPs regarding their location relative to water and sediment pathways. In this work, the authors analyzed the impact of the spatial distribution of LMPs using an existing distributed model and sensitivity analysis procedures. The distributed model that was used is a distributed single-event physically based water erosion model developed to calculate erosion rates and sediment flow for small (less than 10 km2) agricultural catchments. To measure the impact of the spatial distribution of LMPs, the authors developed a stochastic model that generates LMP locations over the entire catchment. The stochastic model has three input parameters: the density of LMPs, their downslope/ upslope location probability, and the probability density function shape controller. Because of its ability to account for the cross effects between parameters, the variance-based Sobol method was used to calculate the sensitivity of the soil loss ratio of a typical Mediterranean agricultural catchment (Roujan, southern France) to the LMP location model parameters. Three measurement points (two subcatchment outlets and the main outlet) were used to examine the spatially distributed effects of the LMP locations. The simulation results indicated that 70% of the variation of the net erosion is explained by variations in LMP density for the main outlet catchment, making LMP density the most sensitive parameter. However, the total Sobol sensitivity indices indicate a strong interaction among the three parameters when the density values are low (few LMPs are applied). Thus, although the density of the LMPs is the most sensitive parameter, their location may influence their global trapping efficiency in (real) cases where few LMPs are applied.

Analyse de sensibilité globale du modèle CATHY aux propriétés hydrodynamiques du sol d’un micro-bassin agricole drainé

Résumé Une étude d’analyse de sensibilité globale d’une application du modèle hydrologique CATHY (CATchment HYdrology) sur un bassin sous influence de drains agricoles a été réalisée en utilisant les méthodes Morris, FAST99 (Fourier Amplitude Sensitivity Test) et Sobol2002. Ces analyses ont permis d’identifier les paramètres les plus sensibles sur : (a) l’écoulement aux drains et (b) les flux sortant du micro-bassin agricole Bras d’Henri (Québec, Canada). Des 24 paramètres évalués par la méthode de Morris, les neuf et huit paramètres ayant été respectivement très influents sur les deux variables de sortie, ont été analysés par les méthodes FAST99 et Sobol2002. Il s’ensuit que la conductivité hydraulique horizontale à saturation dans les couches sous les drains est la propriété hydrodynamique la plus influente sur les deux variables de sortie. Cette étude démontre que des efforts devraient être portés sur la caractérisation de l’anisotropie du sol, car celle-ci n’est pas à négliger lors d’une modélisation hydrologique tridimensionnelle. Editeur Z.W. Kundzewicz Citation Muma, M., Gumiere, S.J., et Rousseau, A.N., 2014. Analyses de sensibilité globale du modèle CATHY aux propriétés hydrodynamiques du sol d’un micro-bassin agricole drainé. Hydrological Sciences Journal, 59 (8), 1606–1623. http://dx.doi.org/10.1080/02626667.2013.843778

Modeling of subsurface agricultural drainage using two hydrological models with different conceptual approaches as well as dimensions and spatial scales

In regions where soils are seasonally or perennially wet, subsurface drainage represents an essential water management practice. Two hydrological models with different modeling approaches as well as different dimensional and spatial scales, DRAINMOD (1D, lumped and field-scale) and CATHY (3D, spatially distributed and watershed-scale), were compared in terms of their performance to predict tile-drain flow and to simulate evapotranspiration (ET) under field conditions. Two metrics were defined to assess the capacity of the models to represent the soil water dynamics: relative errors in simulating peak flow and drainage volume. Using different hydraulic conductivity scenarios, both models provided similar results. For the total predicted/observed tile-drain flow comparison, the two models yielded very similar results. In terms of coefficient of determination (R2) and Nash–Sutcliffe model efficiency (NSE), their performances were low in simulating tile-drain flows for dry periods (low observed tile-drain flow). During periods with higher observed tile-drain flow, the performance of both models was good (R2 > 0.75 and NSE mostly > 0.60), but DRAINMOD produced better results than CATHY did. The two models had similar ET values (R2 > 0.80). Regarding the impact of the hydraulic conductivity of each soil layer on subsurface drainage outflow, this study showed that the soil layer below the tile-drain system was the most influential for the two models.

Relationships among soil hydraulic properties, drainage efficiency, and cranberry yield1

Abstract: In cranberry production, efficient drainage systems are essential for the development of precision irrigation methods. Most cranberry fields are equipped with subsurface drainage systems used for water table control and excess water removal. Cranberries (Vaccinium macrocarpon Aiton) are highly sensitive to wet soil conditions, and decreases in crop yield are often caused by a malfunction of the drainage system. The main objective of this study was to identify the effect of soil hydrodynamic parameters on subsurface drainage efficiency and cranberry production. During the 2013 and 2014 cropping seasons, real-time measurement devices were installed in 15 fields in the Quebec region, to monitor water table drawdown. Characterization of the soil hydrodynamic properties was done on undisturbed soil cores collected from these 15 fields, and the relationships between drainage efficiency and soil properties were determined. The results of this study highlight the importance of soil hydrodynamic properties on water table drawdown and cranberry yield and showed that nearly 50% of the variance of water table drawdown and crop yield is explained by soil hydrodynamic properties.