Determination of stochastic well head protection zones by direct propagation of uncertainties of particle tracks

Kunstmann, Harald; Kastens, Marko

doi:10.1016/j.jhydrol.2005.09.003

Cited by 19 publications

(18 citation statements)

References 29 publications

(34 reference statements)

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“…This is a reasonable simplification, since aquifer heterogeneity adds uncertainty in the prediction of transport pathways and duration, but does not change the long-term recharge contribution from septic drainfields and hence does not change the overall size of the source area, only its actual shape and location (Kunstmann and Kastens, 2006). Since our analysis is already probabilistic with respect to the exact shape and location relative to the lot shape, aquifer heterogeneity would not add to the reported uncertainty.…”

Section: Discussionmentioning

confidence: 99%

“…Subsurface heterogeneity is difficult to assess and typically leads to increased dispersion ("macrodispersion"). Macro-dispersion increases the source area of a well (Kunstmann and Kastens, 2006). Regional groundwater flow direction can typically be retrieved from regional water level contour maps generated by state or federal agencies.…”

Section: Source Area Intersection With Septic Drainfieldsmentioning

confidence: 99%

“…Many studies demonstrated significant correlations of septic system density to contaminant concentrations and disease outbreaks (Schmidt, 1972;Pitt, 1974Pitt, , 1975Konikow et al, 1978;Katz et al, 1980;Duda and Cromartie, 1982;Bicki et al, 1985;Yates, 1985Yates, , 1991Hantzsche and Finnemore, 1992;Nizeyimana et al, 1996;Canter, 1997;Whitehead and Geary, 2000;Borchardt et al, 2011;Standley et al, 2008). In US EPA (1977), the agency specified a septic system density exceeding 40 systems per square mile (1 system per 16 acres) as at risk of groundwater contamination and considered septic system density to be the most important control of contamination risk from septic systems.…”

Section: Introductionmentioning

confidence: 99%

“…Trela and Douglas (1978) and Brown (1980) established dilution models to determine a maximum septic system density for sandy soils. The flow and transport model of Konikow et al (1978) was applied to study effects of septic system densities. Lowe et al (2003), Bishop et al (2007) and Lowe et al (2011) used a groundwater flow model coupled with a mass balance approach to evaluate the risk associated with septic system densities.…”

Section: Introductionmentioning

confidence: 99%

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Domestic wells have high probability of pumping septic tank leachate

Bremer

Harter

2012

Hydrol. Earth Syst. Sci.

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Abstract. Onsite wastewater treatment systems are common in rural and semi-rural areas around the world; in the US, about 25-30 % of households are served by a septic (onsite) wastewater treatment system, and many property owners also operate their own domestic well nearby. Site-specific conditions and local groundwater flow are often ignored when installing septic systems and wells. In areas with small lots (thus high spatial septic system densities), shallow domestic wells are prone to contamination by septic system leachate. Mass balance approaches have been used to determine a maximum septic system density that would prevent contamination of groundwater resources. In this study, a source area model based on detailed groundwater flow and transport modeling is applied for a stochastic analysis of domestic well contamination by septic leachate. Specifically, we determine the probability that a source area overlaps with a septic system drainfield as a function of aquifer properties, septic system density and drainfield size. We show that high spatial septic system density poses a high probability of pumping septic system leachate. The hydraulic conductivity of the aquifer has a strong influence on the intersection probability. We find that mass balance calculations applied on a regional scale underestimate the contamination risk of individual drinking water wells by septic systems. This is particularly relevant for contaminants released at high concentrations, for substances that experience limited attenuation, and those that are harmful even at low concentrations (e.g., pathogens).

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Section: Discussionmentioning

confidence: 99%

Section: Source Area Intersection With Septic Drainfieldsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Domestic wells have high probability of pumping septic tank leachate

Bremer

Harter

2012

Hydrol. Earth Syst. Sci.

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“…The source area size per capita is therefore at least 0.1 ha. Uncertainties about actual groundwater flow direction and about aquifer heterogeneity, and the transient flow dynamics due to seasonal influence of nearby large capacity agricultural irrigation wells lead to areas contributing to recharge of a well to be significantly larger than Equation (2) (e.g., [53,54]. Information regarding groundwater flow, location of community wells, soil characteristics, and current areas of agricultural production may contribute to this determination.…”

Section: Determining Recharge Buffer Zone Areamentioning

confidence: 99%

Economic Feasibility of Irrigated Agricultural Land Use Buffers to Reduce Groundwater Nitrate in Rural Drinking Water Sources

Mayzelle

Viers

Medellín–Azuara

et al. 2014

Water

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Agricultural irrigation leachate is often the largest source for aquifer recharge in semi-arid groundwater basins, but contamination from fertilizers and other agro-chemicals may degrade the quality of groundwater. Affected communities are frequently economically disadvantaged, and water supply alternatives may be too costly. This study aimed to demonstrate that, when addressing these issues, environmental sustainability and market profitability are not incompatible. We investigated the viability of two low impact crops, alfalfa and vineyards, and new recharge basins as an alternative land use in recharge buffer zones around affected communities using an integrated hydrologic, socio-geographic, and economic analysis. In the southern Central Valley, California, study area, alfalfa and vineyards currently constitute 30% of all buffer zone cropland. Economic analyses of alternative land use scenarios indicate a wide range of revenue outcomes. Sector output gains and potential cost saving through land use conversion and resulting flood control result in gains of at least $2.3 billion, as compared to costs of $0.3 to $0.7 billion for treatment options over a 20 year period. Buffer zones would maintain the economic integrity of the region and concur with prevailing OPEN ACCESSWater 2015, 7 13 policy options. Thus, managed agricultural recharge buffer zones are a potentially attractive option for communities facing financial constraint and needing to diversify their portfolio of policy and infrastructure approaches to meet drinking water quality objectives.

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