Ireland
Institution

Teagasc, Agricultural Catchments Programme (ACP), Johnstown Castle Environment Research Centre

Name of site

Castledockerell catchment

Location

The map on the left the catchment location in County Wexford, Ireland. Castledockerell (11.2 km2, catchment “a” in the figure) consists mostly of arable land on brown earth soils overlaying slate bedrock.

Geology

The ACP Catstledockerell catchment lies within the Leinster Terrane and consists of Ordovician green and red-purple buff slate and silt-stone of the Oakland formation. Onsite geophysical surveys indicated stratified layers of highly weathered to strong slate at depths of ca. 2–20 metres. Above the bedrock are highly permeable layers of gravelly clay and lenses of gravel.

Hydrogeology

The aquifer is shallow and unconfined with a poor production. Groundwater flow occurs largely within the permeable subsoil and layers of highly weathered bedrock overlying the bedrock. The groundwater contribution to stream discharge is ca. 96% during a major spring flow event and the annual average over four years is 75%. Hill slope travel times are estimated to be 2-12 months across depths in the dominant pathways.

Monitoring infrastructure

The catchment is extensively monitored and consists of two hill slope study sites with a network of 6 multilevel monitoring wells and 17 piezometers (2”) with 3 m screens at depths between 1 to 50 m below ground. Each piezometer is equipped with a level logger recording water levels every 30 minutes, and is sampled monthly for N, P and metals.

The catchment is equipped with a weather station (BWS200, Campbell Scientific) in the central lowlands. This measures rainfall, air temperature, relative air humidity, global radiation and wind speed on a 10-minute basis. On higher ground there is an additional rain gauge (ARG-100 and Solinst rainlogger) serving as a backup and recording the high altitude rainfall.

Stream water level is recorded on a 10-min basis (2010-2013) with OTT Orpheus Mini vented-pressure instruments installed in stilling wells in the catchment outlet. Unfiltered Total Phosphorus (TP), Total Reactive Phosphorus (TRP) concentrations, electrical conductivity (EC) and turbidity are monitored concurrently using a Hach-Lange Sigmatax-Phosphax and Solitax suite of instruments. This monitoring started in 2009.

Agricultural impacts and pollutant types

The catchment uses ca. 54% of its land for intensive and continuous crop production (mostly spring barley), with a plant available N loading (97% chemical and 3% organic manure and/or cattle slurry) of 136 kg ha-1 and plant available P loading (88% chemical and 12% organic manure and/or cattle slurry) of 26 kg ha-1 during growing seasons (predominantly applied during March to April). The catchment has 80% well drained acid brown earth soils (Cambisols), 16% poorly drained gley soils and 4% alluvial soils.

Available data

The data available for this catchment comprises the following 9including sampling frequency)

  • Weather (10-minute)
  • Groundwater flux (30 minute)
  • Groundwater chemistry (month)
  • Stream water discharge (10 minute)
  • Stream water chemistry (10 minute)
  • Soil nutrient status (3 yr)
  • Land management (season)
  • Geophysical model
  • DEM
Relevant publications
  • Mellander P-E, Jordan P, Shore M, McDonald N, Wall DP, Shortle G, Daly K (2016). Identifying contrasting controls and surface water signals from groundwater phosphorus flux. Science of the Total Environment, 541, 292-302.
  • Mellander P-E, Jordan P, Shore M, Melland AR, Shortle G (2015). Flow paths and phosphorus transfer pathways in two agricultural streams with contrasting flow controls. Hydrological Processes, 29, 3504-3518.
  • Mellander P-E, Melland AR, Murphy PNC, Shortle G, Jordan P (2014). Coupling of surface water and groundwater nitrate-N dynamics in two permeable agricultural catchments. Journal of Agricultural Science, 152, S107-S124.
  • Mellander P-E, Melland AR, Jordan P, Wall DP, Murphy PNC, Shortle G (2012). Quantifying nutrient transfer pathways in agricultural catchments using high temporal resolution data. Environmental Science and Policy, 24, 44-57.
  • Melland AR, Mellander P-E, Murphy P, Wall DP, Mechan S, Shine O, Shortle G, Jordan P (2012). Stream water quality in intensive cereal cropping catchments with regulated nutrient management. Environmental Science and Policy, 24, 58-70.
  • Shore M, Jordan P, Mellander P-E, Kelly-Quinn M, Wall D, Murphy PNC, Melland AR (2014). Source and transport factors influencing storm phosphorus losses in agricultural catchments. Science of the Total Environment, 490, 405-415.
Institution

Teagasc

Name of site

Dairy Farm Johnstown Castle

Location

The study site is located on a 52 hectare dairy farm at Johnstown Castle, Wexford, SE Ireland

Geology

The soils are poor to moderately well-drained fine loam to clay loam (classified as a gleyic cambisol after the World Reference Base (WRB)) derived from Irish Sea till. The site comprises a mature glacial till subsoil (moderate permeability, ks, 5 × 10−8m s−1 to 5 × 10−4m s−1), which is heterogeneous and morainic in nature.

Hydrogeology

The site has been intensively investigated using boreholes, piezometers and 3 sets of multi level boreholes to examine the subsoil, subsoil/bedrock interface and bedrock, down to 30 m in some cases. The aquifer is unconfined and the mean depth of the perched water table within the subsoil is 2.75 m, with a range from 0.72 m to 7.45 m.

Hydrology

It has a temperate maritime climate with a 30-year-average annual rainfall of 1000 mm and a mean daily temperature of 9.6oC.

Monitoring infrastructure

The site has been intensively instrumented with single and multi-level piezometers (>40), which have been sampled monthly to provide a 12 year dataset. The map below shows the layout of the site and the different monitoring infrastructures available. The monitoring well network is open for use in its entirety to facilitate monitoring equipment e.g. sensors or passive samplers. There is a national meteorological-station on site. About 10 Km of mapped drains (open and in-field) are available for sampling surface and subsurface drainage from various managed locations. Open ditch networks have weirs installed to track flows.

Water samples can be taken form all access points. Locally Teagasc has experimental and analytical laboratories to characterise water chemistry, dissolved gases and N2/Ar ratios.











Agricultural impacts and pollutant types

Nitrate and phosphorus data suggest breaches of water quality at some points within the monitoring network.

Available data

The following information and data is available to support research on this site:

  • Soil maps
  • Falling head tests completed on all screened intervals of monitoring wells
  • Water table height data
  • Water quality data (full range of chemistry for 12 years), including surface and groundwater
  • Isotope data taken for all locations
  • Meteorological station data available for +30 years
  • Good farm activity and management data available in high resolution with all inputs documented
Relevant publications
  • Baily, A., L. Rock, C. Watson, and O. Fenton. (2011). Spatial and temporal variations in groundwater nitrate at an intensive dairy farm in south-east Ireland: Insights from stable isotope data. Agriculture, Ecosystems and Environment, 144, 308-318.
  • Jahangir, M. M., P. Johnston, M. Khalil, D. Hennessy, J. Humphreys, O. Fenton, and K. G. Richards. (2012). Groundwater: A pathway for terrestrial C and N losses and indirect greenhouse gas emissions. Agriculture, Ecosystems and Environment, 159, 40-48.
  • Jahangir, M. M. R., P. Johnston, M. I. Khalil, and K. Richards. (2009a). Extent and potential of groundwater denitrification in different hydrogeological and geochemical situations of Ireland. p97 in 19th Annual Irish Environmental Researchers Colloquium, Waterford Institute of Technology, Waterford, Ireland.
  • Jahangir, M. M. R., M. I. Khalil, P. Johnston, K. G. Richards, J. B. Murphy, and D. Brennan. (2009b). Assessment of groundwater denitrification capacity by analysing dissolved gases using Membrane Inlet Mass Spectrometer. pp 33-34 in S. Lalor and D. O' hUallacháin, editors. Ireland’s Rural Environment: Research Highlights from Johnstown Castle Environment Research Center, Teagasc. Teagasc, Johnstown Castle, Wexford.
Research opportunities and additional information
  • The extensive monitoring network (surface and groundwater), data on rainfall and soil profile, could be used to model pollutant transport and attenuation in groundwater. This can be correlated with farm management and soil testing.
  • The facility is open to retrofitting existing monitoring networks with high resolution smart monitoring methodologies, passive samplers, continuous monitoring sensors and probes.
  • Any equipment to collect high resolution flow data would be advantageous.
  • The site hosts open days for farmers and the agricultural industry, which can be used to showcase INSPIRATION activities.

Beneficiaries

Partner Organisations