Sewage plume in a sand and gravel aquifer, Cape Cod, Massachusetts

LeBlanc, Denis R.

doi:10.3133/ofr82274

Cited by 72 publications

(112 citation statements)

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“…Ashumet Pond has an area of about 0.82 km 2 and a maximum depth of 26 m and is a groundwater flow‐through lake, with no surface water outlet and only a minor surface water inlet. The water table aquifer connected hydraulically to Ashumet Pond was contaminated by disposal of treated wastewater onto surface infiltration beds for >60 years (LeBlanc, ; Repert et al, ). A portion of the wastewater contaminant plume discharges into Ashumet Pond in the vicinity of Fishermans Cove (McCobb et al, ; Stoliker et al, ), which is about 2‐years groundwater travel time downgradient from the infiltration bed location.…”

Section: Methodsmentioning

confidence: 99%

Seasonal and Spatial Variation in the Location and Reactivity of a Nitrate‐Contaminated Groundwater Discharge Zone in a Lakebed

et al. 2019

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Groundwater discharge delivering anthropogenic N from surrounding watersheds can impact lake nutrient budgets. However, upgradient groundwater processes and changing dynamics in N biogeochemistry at the groundwater‐lake interface are complex. In this study, seasonal water‐level variations in a groundwater flow‐through lake altered discharge patterns of a wastewater‐derived groundwater contaminant plume, thereby affecting biogeochemical processes controlling N transport. Pore water collected 15 cm under the lakebed along transects perpendicular to shore varied from oxic to anoxic with increasing nitrate concentrations (10–75 μM) and corresponding gradients in nitrite and nitrous oxide. Pore water depth profiles of nitrate concentrations and stable isotopic compositions largely reflected upgradient groundwater N sources and N cycle processes, with minor additional nitrate reduction in the near‐surface lakebed sediments. Potential denitrification rates determined in laboratory microcosms were 10–100 times higher in near‐surface sediments (0–5 cm) than in deeper sediments (5–30 cm) and were correlated with sediment carbon content and abundance of denitrification genes (nirS, nosZI, and nosZII). Potential anammox‐driven N2 production was detectable in deeper anoxic sediments. Injection of bromide and nitrite in the lake sediments showed that the highest net nitrite consumption rates were within the top 10 cm. However, short transit times owing to rapid upward pore water velocities (4–5 cm hr−1) limited removal of the contaminant nitrate transiting through the sediments. Results demonstrate that local hydrologic and biogeochemical processes at the point of discharge affect the distribution and discharge rate of N through lakebed sediments, but processes in the upgradient groundwater can be more important for affecting N speciation and concentration.

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Section: Methodsmentioning

confidence: 99%

Seasonal and Spatial Variation in the Location and Reactivity of a Nitrate‐Contaminated Groundwater Discharge Zone in a Lakebed

et al. 2019

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“…The plume extends in the direc tion of the regional flow of groundwater, and is overlain by 6 to 15 m of groundwater produced by precipitation recharge of the aquifer. Although it was not sampled farther than 3.5 km from the treatm ent plant, the south-and southw est-m oving plume is probably flowing in the direction of the downstream end of the Coonamessett River in East Falmouth and the small streams, ponds, wetlands, and saltwater bays east o f the river 5 km southwest of the head of the plume (LeBlanc, 1982). Sev eral other chemical plumes are also present within and outside the base boundaries.…”

Section: Ia G R a M M A Tic M E A Su R E D S E C T Io N S At H Ig Hmentioning

confidence: 97%

“…It is the human condition to accept solutions that cause the least inconvenience, rather than accept those that may entail some sacrifice. Secondarily treated sewage disposed on surface sand beds since 1936 at the Otis Air Force Base (now called the Massachusetts Military Reservation) sewage treatment facility, for example, has infiltrated the sands into the underlying unconfmed sand and gravel aquifer, producing a 23-m-thick, 760-to 1,970-m-wide, and >3-km -long south-southw esttrending plume of sewage-contam inated and otherw ise pol luted water (LeBlanc, 1982). The plume extends in the direc tion of the regional flow of groundwater, and is overlain by 6 to 15 m of groundwater produced by precipitation recharge of the aquifer.…”

Section: Ia G R a M M A Tic M E A Su R E D S E C T Io N S At H Ig Hmentioning

confidence: 99%

The Late Quaternary Construction of Cape Cod, Massachusetts: A Reconsideration of the W. M. Davis Model

Uchupi¹,

Giese²,

Aubrey³

et al. 1996

The Late Quaternary Construction of Cape Cod, Massachusetts: A Reconsideration of the W. M. Davis Model

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Like the W. M. Davis construction o f Cape Cod published in 1896, this special paper suggests that the Cape was formed by glacial deposition during the late Pleis tocene and by marine and aeolian processes during the Holocene. It differs, however, from the Davis model in several significant ways. For example, Davis proposed that the lower Cape extended 4 km east o f its present location, and that only 4,000 yr were needed for the lower Cape to attain its present form. This study indicates that the glacial Cape extended as far as 7 km east of its present position, and that it took about 9,500 yr for the Cape to attain its present morphology. Davis also believed that the detritus eroded from the sea cliffs on the east side of the lower Cape was trans ported northward to form the Provincetown Hook. On the other hand, this book indi cates that, as a result o f the subaerial exposure o f Georges Bank from 9,500 to 6,000 yr ago, littoral drift to the north was inhibited and sediment was transported south ward to fill a depression at the Cape's elbow. Since Georges Bank became submerged about 6,000 yr ago, however, littoral drift shifted partly to the north, leading to the construction of Provincetown Hook, a process that is still taking place today. The bulk o f material (86%) eroded from the cliffs along the east side of the lower Cape during the last 6,000 yr was transported northward. Of the remainder, 7% was used in the construction o f the beaches and offshore bars fronting the cliffs, and the remaining 7% was incorporated into the spits and barriers south of the cliffs. During the last 70 yr, the eastern Cape cliffs have been retreating at an average rate of 0.8 m a-1, a rate enhanced by a relative rise in sea level of about 2 to 3 mm a-1.

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“…The value of R = 1.2 denotes the start of convergence, an R = 1.0 the total convergence drainage from the vadose zone in the analytical solution proposed [119,122,123]. Finally, the original saturated thickness, b (m), is included, even though there are previous estimates of roughly 49 m [124][125][126].…”

Section: Description Of the Problemmentioning

confidence: 99%

A review of Markov Chain Monte Carlo and information theory tools for inverse problems in subsurface flow

et al. 2011

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Parameter identification is one of the key elements in the construction of models in geosciences. However, inherent difficulties such as the instability of ill-posed problems or the presence of multiple local optima may impede the execution of this task. Regularization methods and Bayesian formulations, such as the maximum a posteriori estimation approach, have been used to overcome those complications. Nevertheless, in some instances, a more in-depth analysis of the inverse problem is advisable before obtaining estimates of the optimal parameters. The Markov Chain Monte Carlo (MCMC) methods used in Bayesian inference have been applied in the last 10 years in several fields of geosciences such as hydrology, geophysics or reservoir engineering. In the present paper, a compilation of basic tools for inference and a case study illustrating the practical application of them are given. Firstly, an introduction to the Bayesian approach to the inverse problem is provided together with the most common sampling algorithms with MCMC chains. Secondly, a series of estimators for quantities of interest, such as the marginal densities or the normalization constant of the posterior distribution of the parameters, are reviewed. Those reduce the computational cost significantly, us-

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Sewage plume in a sand and gravel aquifer, Cape Cod, Massachusetts

Cited by 72 publications

References 0 publications

Seasonal and Spatial Variation in the Location and Reactivity of a Nitrate‐Contaminated Groundwater Discharge Zone in a Lakebed

Seasonal and Spatial Variation in the Location and Reactivity of a Nitrate‐Contaminated Groundwater Discharge Zone in a Lakebed

The Late Quaternary Construction of Cape Cod, Massachusetts: A Reconsideration of the W. M. Davis Model

A review of Markov Chain Monte Carlo and information theory tools for inverse problems in subsurface flow

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