1. WATER YOU LOOKING AT? LAND USE AND WATER QUALITY ON THE DINGLE PENINSULA Elizabeth Bouchard, Jenna Rondeau, Mark Beekey, and LaTina Steele Sacred Heart University, Department of Biology
Introduction
The coastal towns of Dingle and Ballyferriter are located on the southwest coast of Ireland (Figure 1). Dingle has year round population of 2000 residents that swells to 10,000 people in summer months due to tourism. Ballyferriter has 268 year round residents with the physical ability to accommodate a peak seasonal tourist population of 64 people in 16 holiday homes. While both watersheds have similar land use characteristics, Ballyferriter has more scrub type habitat and lower sheep density than Dingle (Table 1). Given temporal differences in population density and land use, we investigated how nutrient levels in streams varied within and across watersheds with respect to yearly differences (2016 vs. 2017).
Figure 5. Average dissolved oxygen(+/- 1 S.E.) concentrations for Dingle and Ballyferriter watersheds.
Figure 2. Ballyferriter Watershed (left) and Dingle Watershed (right), describing the breakdown of land usage.
Conclusions
While Ballyferriter is slightly larger than the Dingle watershed, both watersheds have similar development and farm/pasture land use acreage (Table 1). Dingle contains more sheep per acre than Ballyferriter.
pH increased in the Dingle watershed over the time period sampled however for Ballyferriter, pH decreased in 2016 but increased in 2017 between the months of June and July. (Figure 3).
As one might expect, nitrate levels increased from 2016 to 2017, (Figure 4 – left panel). One explanation for this could be high densities of human tourists during the summer months.
Phosphate levels are decreasing in the Dingle watershed. Ballyferriter increases between the months of June and July for both years. (Figure 4-left panel)
Dissolved oxygen increased slightly over the two years for both watersheds. (Figure 5)
Dingle (km2)
Ballyferriter (km2)
Watershed Area
50.1
64.0
Scrub
19.2
37.1
Forest
3.1
1.4
Farm/Pasture
25.1
24.2
Developed
2.3
2.2
# sheep
8691
11127
Sheep density 16
13.3
Table 1. Describes the breakdown of land usage between the Dingle and Ballyferriter watersheds.
Figure 1. The Dingle Peninsula is located on the Southwest part of Ireland. The Dingle watershed is highlighted in dark blue, and the Ballyferriter watershed is highlighted in light blue.
Figure 3. Average pH (+/- 1 S.E.) concentrations for Dingle and Ballyferriter watersheds.
Methods
Water samples were collected from one river in each watershed. The Milltown River in the Dingle watershed and the Feohanagh River in the Ballyferriter watershed
Sampled once a week from June 14th, 2016 to July 18, 2016 as well as June 13th, 2017 to July 17th, 2017
Indices such as DO and pHwere recorded at each location. N > 8 for Dingle and N>5 for Bally at each sampling time) (Temp and salinity not presented)
Nitrate and phosphate were determined using colorimetric assays (Hach DR2400 Spectrophotometer). N > 8 for Dingle and N>5 for Bally at each sampling time)
Acknowledgements
Many thanks to Kevin Flannery (Director) and the staff at Mara Beo for assistance with field sampling and space to process samples.
Figure 4. Average nitrate (NO3) and phosphate (PO4) levels (mg/L) (+/- 1 S.E.) for each watershed. Nitrate is shown on the left and phosphate is located on the right.