Includes Llyn Dinam SAC.

This site, situated at the northern end of a busy military airfield, comprises Llyn Penrhy, Llyn Dinam and Llyn Treflesg (largely within the RSPB Llynnau Y Fali reserve) along with Llyn Cerig bach and other small pools. This series of small shallow lakes supports a varie aquatic flora and fauna. However, enrichment of Llyn Penrhyn, in particular, by effluent from the RAF base, has compromised the ecological integrity of the site. Despite pioneering use of phosphate stripping technology by the MoD since 1995, phosphate levels in Llyn Penrhyn remain alarmingly high, probably due to recycling of material from the lake sediments. This threatens to flip the lake into an algal-dominated state which would eliminate most of the flora and fauna for which the site is valued.

There is a small RSPB car park north of the railway line. Aircraft noise can be very intense during weekdays - you can smell the aviation fuel - so the site can be more peaceful in early morning, evening or weekends.

Anglesey map

SSSI Citation

Potentially Damaging Operations list

Site Management Statement

Special Area of Conservation

Vertical Aerial Photograph

Map reproduced by permission of Ordnance Survey ® on behalf of the Controller of Her Majesty's Stationery Office. © Crown copyright. All rights reserved. License number 100044910.