THE ISOTOPE BIOGEOCHEMISTRY OF LANDFILL
REFUSE-IMPACTED GROUNDWATER.Current PhD research
THE ISOTOPE BIOGEOCHEMISTRY OF LANDFILL
REFUSE-IMPACTED GROUNDWATER.
SIMULATION OF THE IMPACTS OF CLIMATE
CHANGE ON GROUNDWATER RESOURCES
WATERSHED DELINEATION AND GROUNDWATER
DISCHARGE TO THE NORTH NORFOLK COAST
THE ISOTOPE BIOGEOCHEMISTRY OF LANDFILL
REFUSE-IMPACTED GROUNDWATER.
Andrea Lancaster
Summary : Landfill leachate is highly contaminating to
groundwater with many old, unlined landfills now posing a pollution threat to
aquifers. To monitor this pollution, a stable isotope technique is proposed,
which although previously applied to many geochemical and hydrogeological
studies has not extensively been used in investigations of the impact of
leachate on groundwater. The stable isotopes to be measured are S-34, O-18,
N-15, C-13 and H-2. Sampling at groundwater/leachate boreholes in and around
landfill sites situated on the lower Cretaceous sands and the upper Cretaceous
chalk in Norfolk has been undertaken. As a control on field results and
interpretation, controlled laboratory experiments simulating solute transport
reactions are to be carried out. A series of columns mounted in a controlled
temperature laboratory, packed with aquifer materials and subjected to
injection of synthetic leachate, will be continuously monitored for electrical
conductivity and sampled for major ion and stable isotope composition.
SIMULATION OF THE IMPACTS OF CLIMATE
CHANGE ON GROUNDWATER RESOURCES.
Ismail Yusoff
Summary : It is apparently difficult to identify the
practical significance of climate change on groundwater resources. But, it is
possible to evaluate the effects by assuming that the future will statistically
replicate the hydrological and hydrogeological regimes recorded in the past.
The main task of the study is to develop an alternative method to evaluate
climate change effects on water resources. The aim is to test the idea of using
an established specific numerical groundwater model to assess the impacts. The
USGS groundwater flow model, MODFLOW has been chosen because the 'Recharge'
package of the model allows different values of groundwater recharge for
different stress periods. The outputs from the climate model (General
Circulation Model, GCM) will be used to generate different climate scenarios
leading to variable groundwater recharges for the future. As the calculation of
groundwater recharge is very subjective, a consistent way of calculation has to
be chosen. An area in West Norfolk which is described as a 'semi-arid' area
(annual rainfall less than 600mm) has been selected as the study area. The area
is expected to have groundwater resource difficulties under predicted future
climate scenarios. A calibrated steady state model using current climatic
conditions will be used as the initial condition for a transient model
calibration. The calibrated transient model will be used with future climate
scenarios and the effects on groundwater levels, river baseflow and groundwater
reasources will be evaluated, and finally concluded. It is hoped that the study
will at least provide a greater understanding of the area to the field of
hydrogeology.
WATERSHED DELINEATION AND GROUNDWATER
DISCHARGE TO THE NORTH NORFOLK COAST
Adrian Green
Summary: The coastal zone of north Norfolk between Weybourne and Hunstanton comprises a Holocene wedge of intertidal sediments that was deposited and shaped by sea-level change (Pearson & Funnell, 1989; Andrews et al. in press). Following the last glacial maximum and the recovery of sea-level, this coastal zone has been rolled landward (south) and has developed into a system of marine muds and silts accumulating in saltmarsh and intertidal flat environments, protected from the sea by wave-formed sand and shingle barriers.
The landward limit of this Holocene wedge is fixed by the rising topography to the south formed by the underlying Pleistocene glacial and Cretaceous Chalk deposits. The surface water catchments of the Rivers Burn, Glaven and Stiffkey drain to the coastal zone and are strongly supported by Chalk groundwater baseflow. Additionally, and from initial water balance calculations, direct runoff to the coast may be as much as 54% of the mean annual recharge to these catchments (Altchenko, 1998). The Environment Agency’s LEAP report for North Norfolk recognises this area for regional level investigation and the importance of its internationally recognised coastal habitats. Within this context, and in the absence of current detailed hydrogeological knowledge, this studentship aims to delineate accurately the groundwater catchments and mechanisms of groundwater discharge to the North Norfolk coast. This important baseline information will be used in the future to calculate hydrochemical fluxes in this coastal zone, both today and over the Holocene; these fluxes have proved very significant in the few other studies that have been attempted (Moore, 1996).
The research will incorporate information on the Holocene geology and sub-surface structure collected as part of the NERC LOIS programme (Andrews et al. in press), and also extend the hydrogeological database held by the Environment Agency. Fieldwork will be required to map springs and seepages, monitor river flows and install shallow well points for water level measurement and sampling. The project is expected to produce a detailed hydrogeological map of the North Norfolk coast together with catchment water balances for the Rivers Burn, Glaven and Stiffkey. Conceptual hydrogeological models at local and regional scales will be tested with groundwater models such as MODFLOW (flow model) and TARGET (density-coupled solute transport model) and used to provide an overall interpretation of the significance of freshwater fluxes to the coastal zone. In addition, it may be possible to predict how these fluxes have changed over the last 10,000 years by integrating the hydrogeological models with our understanding of how the geometry of the Holocene sediment prism has changed over this time.
References:
ALTCHENKO, Y. 1998. A theoretical study of groundwater discharge along the
North Norfolk coast, UK. MSc Thesis, University of East Anglia, 52 pp.
ANDREWS, J.E., BOOMER, I., BAILIFF, I., BALSON, P., BRISTOW, C., CHROSTON, P.N., FUNNELL B.M., HARWOOD, G.M., JONES, R.W. MAHER, B.A, & SHIMMIELD, G. (in press) Sedimentary evolution of the north Norfolk barrier coastline in the context of Holocene sea-level change. In: Land Ocean Evolution Perspectives Study. (Ed. by I. Shennan and J.E. Andrews), Geological Society Special Publication No.x.
FUNNELL, B. M. & PEARSON, I. 1989. Holocene sedimentation on the North Norfolk barrier coast in relation to relative sea-level change. Journal of Quaternary Science, 4, 25-36. MOORE, W.S. 1996. Large groundwater inputs to coastal waters revealed by 226Ra enrichments. Nature, 380, 612-614.
Back to Hydrogeology at UEA
Back to ENV Homepage
Back to UEA Homepage
a.foley@uea.ac.uk
Last updated Dec.'99