Teagasc, Agricultural Catchments Programme (ACP), Johnstown Castle Environment Research
Name of site
The map on the left the catchment location in County Wexford, Ireland. Castledockerell (11.2
catchment “a” in the figure) consists mostly of arable land on brown earth soils overlaying
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.
metres. Above the bedrock are highly permeable layers of gravelly clay and lenses of gravel.
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.
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
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%
and/or cattle slurry) of 26 kg ha-1 during growing seasons (predominantly applied
to April). The catchment has 80% well drained acid brown earth soils (Cambisols), 16% poorly
drained gley soils and 4% alluvial soils.
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
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.
Name of site
Dairy Farm Johnstown Castle
The study site is located on a 52 hectare dairy farm at Johnstown Castle, Wexford, SE
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.
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.
It has a temperate maritime climate with a 30-year-average annual rainfall of 1000 mm and a mean
daily temperature of 9.6oC.
The site has been intensively instrumented with single and multi-level piezometers (>40),
have been sampled monthly to provide a 12 year dataset. The map below shows the layout of
site and the different monitoring infrastructures available. The monitoring well network is
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
Agricultural impacts and pollutant types
Nitrate and phosphorus data suggest breaches of water quality at some points within the
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
- 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
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.