A hydro-economic modelling framework for optimal management of groundwater nitrate pollution from agriculture

A hydro-economic modelling framework is developed for determining optimal management of groundwater nitrate pollution from agriculture. A holistic optimization model determines the spatial and temporal fertilizer application rate that maximizes the net benefits in agriculture constrained by the quality requirements in groundwater at various control sites. Since emissions (nitrogen loading rates) are what can be controlled, but the concentrations are the policy targets, we need to relate both. Agronomic simulations are used to obtain the nitrate leached, while numerical groundwater flow and solute transport simulation models were used to develop unit source solutions that were assembled into a pollutant concentration response matrix. The integration of the response matrix in the constraints of the management model allows simulating by superposition the evolution of groundwater nitrate concentration over time at different points of interest throughout the aquifer resulting from multiple pollutant sources distributed over time and space. In this way, the modelling framework relates the fertilizer loads with the nitrate concentration at the control sites. The benefits in agriculture were determined through crop prices and crop production functions. This research aims to contribute to the ongoing policy process in the Europe Union (the Water Framework Directive) providing a tool for analyzing the opportunity cost of measures for reducing nitrogen loadings and assessing their effectiveness for maintaining groundwater nitrate concentration within the target levels. The management model was applied to a hypothetical groundwater system. Optimal solutions of fertilizer use to problems with different initial conditions, planning horizons, and recovery times were determined. The illustrative example shows the importance of the location of the pollution sources in relation to the control sites, and how both the selected planning horizon and the target recovery time can strongly influence the limitation of fertilizer use and the economic opportunity cost for meeting the environmental standards. There is clearly a trade-off between the time horizon to reach the standards (recovery time) and the economic losses from nitrogen use reductions. (C) 2009 Elsevier B.V. All rights reserved.The authors thank the Editor, Geoff Syme, and two anonymous reviewers for their detailed and helpful comments on improving the paper. Support for this research was provided by the Mexican Ministry of Science and Technology (CONACyT).Peña Haro, S.; Pulido-Velazquez, M.; Sahuquillo Herráiz, A. (2009). A hydro-economic modelling framework for optimal management of groundwater nitrate pollution from agriculture. Journal of Hydrology. 373(1-2):193-203. doi:10.1016/j.jhydrol.2009.04.024S1932033731-

Modeling the response of a karstic quifer with a phisically based linear approach. Case study of Arteta Spring in Spain

A linear response model based on daily spring discharges has been applied in simulating the response of the karstic aquifer feeding the Arteta spring in Navarra (Spain), which is used for the water supply of the city of Pamplona. The model is derived from the eigenvalue solution of the ground-water flow partial differential equation, a method that provides a continuously in time solution of this equation for finite-difference or finite-element space discretization. The modeling approach explains the recession curves composed by several decreasing exponentials observed in many karstic aquifers and differs from the classic assumption where the recession coefficients of these exponentials are identified with different flow regimes in conduit zones. Recharge-discharge transfer has been simulated using a limited number of parameters without having to resort to methods where the impulse-response function of the system is obtained by deconvolution.Estrela Monreal, T.; Sahuquillo Herráiz, A. (1997). Modeling the response of a karstic quifer with a phisically based linear approach. Case study of Arteta Spring in Spain. Groundwater. 35(1):18-24. doi:10.1111/j.1745-6584.1997.tb00055.xS1824351Willis, J. C. (1987). Closure to «Flow Resistance in Large Test Channel» by Joe C. Willis (December, 1983). Journal of Hydraulic Engineering, 113(1), 110-111. doi:10.1061/(asce)0733-9429(1987)113:1(110)Atkinson, T. C. (1977). Diffuse flow and conduit flow in limestone terrain in the Mendip Hills, Somerset (Great Britain). Journal of Hydrology, 35(1-2), 93-110. doi:10.1016/0022-1694(77)90079-8Dreiss, S. J. (1982). Linear kernels for Karst Aquifers. Water Resources Research, 18(4), 865-876. doi:10.1029/wr018i004p00865T. Estrela, 1991 . Estimation de parametros de recarga y descargaen un modelo de flujo subterraneo de un manantial carstico . Tesis Doctoral (Ph.D. dissertation). UPV, Valencia, Espana.J. Forkasiewicz, and H. Paloc . 1965 . Le regime de tarissement de la Foux de la Vis . Coll. Hyd. Roc. Fiss. I. A. H.S. Publ. No. 73, pp. 213 -226 .Gobierno, Foral, and Navarra . 1982 . Estudio de los macizos carsticos de la Navarra Occidental . Proyecto Higrogeologico de Navarra (2 fase). Pamplona, Espana.B. Lopez Camacho, 1981 . Metodo simplificado de gestion de acuiferos para una integration en sistemas de explotacion conjunta . IV Asamblea Nacional de Geodesiay Geofisica, Zaragoza, Espana.O. E. Maillet, 1905 . Essais d'hydraulique souterraine et fluviale . Hermann, Paris. 218 pp.Neuman, S. P., & De Marsily, G. (1976). Identification of linear systems response by parametric programing. Water Resources Research, 12(2), 253-262. doi:10.1029/wr012i002p00253Nutbrown, D. A. (1975). Normal mode analysis of the linear equation of groundwater flow. Water Resources Research, 11(6), 979-987. doi:10.1029/wr011i006p00979Nutbrown, D. A., & Downing, R. A. (1976). Normal-mode analysis of the structure of baseflow-recession curves. Journal of Hydrology, 30(4), 327-340. doi:10.1016/0022-1694(76)90116-5Rosenbrock, H. H. (1960). An Automatic Method for Finding the Greatest or Least Value of a Function. The Computer Journal, 3(3), 175-184. doi:10.1093/comjnl/3.3.175Sahuquillo, A. (1983). An eigenvalue numerical technique for solving unsteady linear groundwater models continuously in time. Water Resources Research, 19(1), 87-93. doi:10.1029/wr019i001p00087A. Sahuquillo, J. Andreu, and J. Capilla . 1985 . Solution de un problema lineal de flujo subterraneo por el metodo de los auto-valores usando elementos finitos . Aplicaciones del metodo de los elementos finitos en Ingenieria. E.T.S. Ingenieros de Caminos, Barcelona, Spain.Soulios, G. (1991). Contribution à l’étude des courbes de récession des sources karstiques: Exemples du pays Hellénique. Journal of Hydrology, 124(1-2), 29-42. doi:10.1016/0022-1694(91)90004-2Thornthwaite, C. W. (1948). An Approach toward a Rational Classification of Climate. Geographical Review, 38(1), 55. doi:10.2307/21073

Estudio del aislamiento de residuos radioactivos en formaciones geologicas profundas: posibles actuaciones en España

Peer Reviewe

Influence of Hydraulic Conductivity and Wellbore Design in the Fate and Transport of Nitrate in Multi-aquifer Systems

Nitrate concentrations in multi-aquifer systems are heavily affected by the presence of wellbores (active or abandoned) that are screened in several aquifers. The spatial variability of hydraulic conductivity in the confining layers has also an important impact on the concentrations. A synthetic three-dimensional flow and transport exercise was carried in a multi-aquifer system consisting of two aquifers separated by an aquitard in which 100 vertical wellbores had been drilled. To model the wellbores and the flow and transport connection between aquifers that they may induce, we assign a high vertical hydraulic conductivity and a low effective porosity to the cell blocks including the wells. With these parameters, a solute will travel quickly from one aquifer to the other without being stored in the well itself. The wellbores will act as preferential pathways, and the solute will move quickly between aquifers according to the hydrodynamic conditions. Not considering these preferential pathways could induce erroneous interpretations of the solute distribution in an aquifer. We also noted that when there are vertical wellbores that connect aquifers in a multi-aquifer system, low conductivity in the aquitard enhances the flow of solute through the wellbores. Time-varying pumping rates induce important fluctuations in nitrate concentrations; therefore, any estimate of the water quality of the aquifer will depend on the moment when the data has been recorded. Consequently, concentration maps obtained by interpolation of point samples are seldom a good indicator of the chemical status of groundwater bodies; alternatively, we recommend complementing the usual interpolated maps with numerical models to gain a true understanding of the spatial distribution of the solute concentration. © 2012 International Association for Mathematical Geosciences.The studies in which this paper is based on have been partially funded by the Spanish MICIN (Ministerio de Ciencia e Innovacion) CGL2008-06394 C02-01 project.Mejía, A.; Cassiraga, EF.; Sahuquillo Herráiz, A. (2012). Influence of Hydraulic Conductivity and Wellbore Design in the Fate and Transport of Nitrate in Multi-aquifer Systems. Mathematical Geosciences. 44(2):227-238. https://doi.org/10.1007/s11004-012-9388-3S227238442Arumí JL, Núñez J, Salgado L, Claret M (2006) Evaluación del riesgo de contaminación con nitrato de pozos de suministro de agua potable rural en Chile (zona de parral). Rev Panam Salud Pública 20:385–392. doi: 10.1590/S1020-49892006001100004Bonton A, Rouleau A, Bouchard C, Rodriguez M (2011) Nitrate transport modeling to evaluate source water protection scenarios for a municipal well in an agricultural area. Agric Syst 104:429–439. doi: 10.1016/j.agsy.2011.02.001Butler J, Whittemore D, Zhan X, Healey J (2004) Analysis of two pumping tests at the O’Rourke bridge site on the Arkansas River in Pawnee County, Kansas. Resources. KGS Open File Report 2004–32, Kansas Department of Agriculture, Division of Water. http://www.kgs.ku.edu/Hydro/Publications/2004/OFR04_32/larned_pumping.pdfCarbó LI, Flores MC, Herrero MA (2009) Well site conditions associated with nitrate contamination in a multilayer semiconfined aquifer of Buenos Aires Argentina. Environ Geol 57:1489–1500. doi: 10.1007/s00254-008-1426-6Cionchi J, Redin I (2004) La contaminación del agua subterránea producida por las deficiencias constructivas en las perforaciones. Obras sanitarias MGP. Gerencia de Planificación y Administración de Recursos Hídricos—Obras Sanitarias Mar del Plata SE. Proyecto REDESAR. http://www.osmgp.gov.ar/web001/documentos/pdf/la_contaminacion_del_agua.pdfElci A, Molz FJ, Waldrop WR (2001) Implications of observed and simulated ambient flow in monitoring wells. Ground Water 39(6):853–862. doi: 10.1111/j.1745-6584.2001.tb02473.xHarbaugh AW, Banta ER, Hill MC, McDonal MG (2000) MODFLOW-2000, the US Geological Survey modular ground water model. User guide to modularization concepts and the ground water flow process. US Geological Survey Open-File Report 00-92Konikow LF, Hornberger GZ (2006) Modelling effects of multimode wells on solute transport. Ground Water 44(5):648–660. doi: 10.1111/j.1745-6584.2006.00231.xKozuskanich J, Novakowski KS, Anderson BC (2011) Fecal indicator bacteria variability in samples pumped from monitoring wells. Ground Water 49(1):43–52. doi: 10.1111/j.1745-6584.2010.00713.xLacombe S, Sudicky EA, Frape SK, Unger AJ (1995) Influence of leaky boreholes on cross-formational groundwater flow and contaminant transport. Water Resour Res 31(8):1871–1882. doi: 10.1029/95WR00661Landon MK, Jurgens BC, Katz BG, EbertS SM, Burow KR, Crandall CA (2010) Depth dependent sampling to identify short-circuit pathways to public supply wells in multiple aquifer settings in the United States. Hydrogeol J 18(3):577–593. doi: 10.1007/s10040-009-0531-2Ma R, Zheng C, Tonkin M, Zachara M (2011) Importance of considering intraborehole flow in solute transport modeling under highly dynamic flow conditions. J Contam Hydrol 123:11–19. doi: 10.1016/j.jconhyd.2010.12.001Mayo L (2010) Ambient well-bore mixing, aquifer cross-contamination, pumping stress, and water quality from long-screened wells: What is sampled an what is not? Hydrogeol J 18:823–837. doi: 10.1007/s10040-009-0568-2Moratalla A, Gómez J, Heras J, Sanz D, Castaño S (2009) Nitrate in the water-supply wells in the Mancha Oriental Hydrogeological System (SE Spain). Water Resour Manag 23:1621–1640. doi: 10.1007/s11269-008-9344-7Reilly TE, Franke OL, Bennett GD (1989) Bias in groundwater samples caused by wellbore flow. J Hydraul Eng 115(2):270–276Spalding RF, Exner ME (1993) Occurrence of nitrate in groundwater—A review. J Environ Qual 22:392–402Wolfe AH, Patz JA (2002) Reactive nitrogen and human health: acute and long term implications. J Hum-Environ Syst 31(2):120–125. doi: 10.1579/0044-7447-31.2.120Zheng C, Wang P (1999) MT3DMS. Department of Geological Sciences, Army Corps of Engineer

La gestión de las aguas subterráneas (Primera Parte)

La Directiva Marco del Agua supone una mejora para la gestión y protección de los aquíferos en España, estableciendo la necesidad de realizar estudios para controlar las extracciones, contaminación y calidad a través de redes piezométricas y su relación con el entorno. El agua subterranea es más eficiente y barata que la superficial procedente de embalses y canales (a pesar de estar muy subvencionada) en España se aplica para regar el 30% de la superficie de riego (unos 3'5 millones de ha.) con un crecimiento espectacular en los últimos 30 años, especialmente en zonas áridas o semidesérticas. Supone el 20% del agua aplikcada al riegoPeer ReviewedPostprint (published version

Quantitative stresses and monitoring obligations

Postprint (published version

Behaviour of battened composite columns

SIGLEAvailable from British Library Document Supply Centre- DSC:D73064/87 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

La gestión de las aguas subterráneas (Segunda parte)

La Directiva Marco del Agua supone una mejora para la gestión y protección de los aquíferos en España, estableciendo la necesidad de realizar estudios para controlar las extracciones, contaminación y calidad a través de redes piezométricas y su relación con el entorno. El agua subterranea es más eficiente y barata que la superficial procedente de embalses y canales (a pesar de estar muy subvencionada) en España se aplica para regar el 30% de la superficie de riego (unos 3'5 millones de ha.) con un crecimiento espectacular en los últimos 30 años, especialmente en zonas áridas o semidesérticas. Supone el 20% del agua aplicada al riegoPeer Reviewe