Surface water process and groundwater flow within a hydrologically complex floodplain wetland, Norfolk Broads, U.K.

Abstract

Abstract. The patterns of variation in water quality for an acidic stream draining plantation forest overlying acidic and acid sensitive gley soils with shale and slate bedrock changed following the introduction of a 45 m deep borchole near to the stream. During drilling, air flushing of debris from the borehole cleared fracture routes for groundwater penetration to the stream via the stream bed. Consequently, there were and there remain marked increases in pH, alkalinity and calcium concentrations in the stream water. The extent of this water quality improvement varies according to flow. Under extreme highfiow conditions, most of the stream water is supplied from near surface soil water sources and acidic stream waters (pH about 4.2) result. Under baseflow conditions, the stream water pH is about 7.0 upstream and about 7.5 downstream of the borehole. Under intermediate flow conditions, the improvement in pH is most marked and values increase from around 5 to around 6.3. For acid sensitive "hard rock" areas such as those studied here, the bedrock has frequently been assumed to be both impermeable and low in base cations. This study illustrates that this view may be incorrect, and that groundwater may provide an important modifier of streamwater quality, at least for slate and shale dominated hard rock areas. Indeed, the work demonstrates clearly the potential for water quality remediation through groundwater manipulation.

Indicators of nitrate in wetland surface and soil-waters: interactions of vegetation and environmental factors

“…Studies of various wetland systems have provided evidence that the underlying hydrology is often both complex and difficult to quantify (Grieve et al, 1995;Gilvear et al, 1997). Within individual sites, variations in hydrological and hydrochemical regimes are major factors driving wetland vegetation composition and structure, (Sjors, 1950;Gorham, 1953;Ingram, 1967;Damman and Dowhan, 1980;Malmer, 1986;Mountford and Chapman, 1993;Kennedy, 2001), and may control the distribution of individual species (Brown and Scott, 1997;.…”

The impact of groundwater–surface water interactions on the water balance of a mesoscale lowland river catchment in northeastern Germany

“…The importance of the interactions between the shallow groundwater and surface waters for water balance processes of floodplains and wetlands in lowland areas (Waddington et al, 1993;Devito et al, 1996;Andersen, 2004), and subsequently for floodplain ecology (Brunke and Gonser, 1997;Gilvear et al, 1997;GascaTucker and Acreman, 2000;Hayashi and Rosenberry, 2002), have been investigated for numerous differently scaled streams and catchments.…”

Hydrological Dynamics II: Groundwater and Hydrological Connectivity

“…Location Scale Groundwater model Poelman and Joosten (1992) Netherlands Conceptual/Regional SIMGRO (1D) Papatolius (1994) Devon, England Local MODFLOW (2D) Wassen et al (1990a) Polder (Netherlands) Local FLOWNET (2D) Bradley C. (1996) Floodplain wetland (England) Local MODFLOW (2D) Gilvear et al (1993) Fen (England) Regional and local MODFLOW (2D) Gilvear et al (1997) Marsh (England) Local MODFLOW (2D) Gerla and Matheney (1996) Prairie pothole North Dakota, USA Local MODFLOW (1D) Hensel and Miller (1991) Floodplain wetland Illinois, USA Regional and local MODFLOW (2D) McNamara et al (1992) Kettle hole wetland Canada Local MODFLOW (2D) Schot and Molenaar Floodplain wetland Netherlands Local FLOWNET Reeve et al (2001) Glacia Lake Agaassiz Peatlands; N. Minnesota, USA…”

“…Predicting the amount of water loss is problematic even if the cone of depression can be measured or modelled using robust groundwater fl ow Gilvear et al (1997) found that geological information revealed that the peatland was separated from an underlying chalk/crag aquifer by approximately one metre of low permeability clay. As a result of this feature, any attempts to model the groundwater fl ow and predict the effects of groundwater abstraction would probably have predicted only a limited hydrological effect, however, both spatially intensive probing and water quality surveys revealed the presence of windows in the clay.…”