Catchment Significant Pressures and Issues Description:
The significant issues identified for the Lingaun_010 were phosphate and sediment with forestry identified as a significant pressure for the third cycle. This waterbody deteriorated to moderate status in 2013-2018. EPA biological assessment at the monitoring point in 2020 recorded a Q Value of 3-4* (* siltation impact). As the waterbody has a high status objective, it is very sensitive to low levels of inputs, and therefore all risks to water quality will be referred where identified. This restore referral is being issued to highlight issues around felling and measures that are needed to minimise risk of sediment loss to the river.
“Description of Referral Area: The referral area relates to the section of the Lingaun_010 immediately upstream of referral point, 16L010050_1150 (See Map 1). Eleven hectares of privately owned forestry adjacent to the waterbody for approximately 600 metres was clear felled in 2023. This was the only area of recently felled forestry identified during local catchment assessment in the waterbody.”
Referral Significant Issue (s) Description
SSIS was undertaken at EPA operational station: Br u/s Whitehall Br (RS16L010050; 16L010050_0100 point on Map 1) in July 2023. The site was found to be Probably not Significantly Impacted with a score of 8. However, tolerant taxa were present in excessive numbers and the site was not considered to be meeting high status requirements. Moderate to high levels of interstitial sediment were also noted. Chemistry sampling in August 2023 and January 2024 did not show any exceedances of the EQS thresholds.
A catchment walk was undertaken in August 2023 in the clearfelled area 2 km upstream from Br u/s Whitehall Br. It was found that buffers had been maintained in some areas but absent in other areas with clearfelling occurring right up to the river bank. In-drain sediment screens were in use in the clearfelled area but some were operating more effectively than others. Some were found to have disintegrated while others were likely to be bypassed in high flow situations. One sediment screen had been erected in a tributary of the waterbody.
Recommendation: This waterbody has a high status objective but is currently at moderate status. Collapsed and not functioning siltraps (found in the area above 16L010050_1150) can potentially release stored fine sediment to the river during rainfall events. Note that sediment issues were found at the EPA monitoring location downstream during LAWPRO local catchment assessment and EPA Q-value assessment. It would be recommended to ensure the adequate functioning of the siltraps in the referral area and ensure their maintenance after clearfelling activities.