Laugharne Estuary water testing-August 2026

Laugharne Estuary Water Quality Report

Monthly Comparative Analysis: August 2026 vs. Previous Months

August 2026 recorded significant water quality improvements across the Laugharne Estuary, showing a strong recovery from the elevated nutrient and ammonia levels observed during earlier summer months (particularly May and July). Increased marine flushing alongside reduced catchment discharge has restored key indicators to safe, natural baseline ranges.

Key Highlights for August 2026

Nutrient Levels Dropped to Baseline: Both Phosphate (PO₄³⁻) and Low-Range Nitrate (NO₃⁻-N)returned to pristine, healthy baseline levels across sampling locations, fully recovering from spikes logged in July.

Ammonia Pollution Alert Cleared: Ammonia (NH₃/NH₄⁺) levels at Path by Steps dropped from a critical 2.50 mg/L spike in July down to a mild 0.29 mg/L, while Frog Rock registered a clean 0.00 mg/L.

Stronger Marine Flushing: High-tide salinity reached its highest levels of the testing season (32.5–32.8 ppt), confirming robust ocean water influx and effective dilution.

Stable Physical Parameters: Dissolved oxygen, pH, and alkalinity remained in optimal ranges for marine and estuarine aquatic life.

2. Parameter-by-Parameter Breakdown

2.1 Nutrients (Phosphate, Nitrate, Nitrite)

Phosphate (PO₄³⁻): Dropped to 0.07 mg/L at both sampling sites. This is a marked improvement from July (where Frog Rock spiked to 0.45 mg/L) and places the estuary comfortably within the clean/good baseline range (< 0.10 mg/L).

Nitrate LR (NO₃⁻-N): Returned to low, healthy levels (0.13 mg/L at Frog Rock, 0.09 mg/L at Path by Steps). This resolves the severe July spike at Path by Steps (2.88 mg/L).

Nitrite (NO₂⁻): Remained virtually non-existent (0.000–0.001 mg/L), showing that organic nitrogen conversion in the estuary is functioning smoothly with no signs of active waste saturation.

2.2 Water ChemistryToxicity Drivers (Ammonia, pH, Alkalinity)

Ammonia (NH₃/NH₄⁺): Frog Rock logged 0.00 mg/L (unpolluted baseline). Path by Steps improved drastically from its July pollution event (2.50 mg/L), though its reading of 0.29 mg/L remains slightly elevated and worth ongoing observation.

Marine pH: Steady at 7.9–8.0, sitting right in the ideal alkaline baseline (7.8–8.2) for high-tide seawater.

=Alkalinity: Measured 6.4–6.5 dKH (~114–116 ppm CaCO₃), providing adequate buffering capacity against pH fluctuations.

2.3 Water Conditions (Dissolved Oxygen, Salinity, Temperature)

Dissolved Oxygen (DO): Ranged between 8.6 and 8.9 mg/L, comfortably inside the 7.0–11.0 mg/L target for healthy, fully oxygenated estuarine water.

Salinity: Peak readings for the year at 32.8 ppt (Frog Rock) and 32.5 ppt (Path by Steps), reflecting strong ocean tidal intrusion and effective dilution.

Water Temperature: Slightly cooled to 20.0°C–20.8°C after peaking at summer highs of

22.2°C–22.6°C in July.