Initial estimates suggest the scheme will have a dramatic adverse effect on kayaking. The dewatered section of the Conwy, known locally as the Fairy Glen, is extremely important for UK paddlers. If the scheme goes ahead there will be a 42% drop in the amount of time when this section will have enough water to paddle.
The Fairy Glen is a classic section of river for white water kayaking and can be considered one of a small number of test piece runs in the UK. As well as having continuous, high quality, challenging rapids, this part of the Conwy is also important to paddlers because it runs very regularly. Other sections of similar quality & difficulty are usually found much higher in their catchments and so need very high water levels before flow is sufficient for kayaking. By contrast, the Fairy Glen is a narrow gorge in the lower reaches of a large river system. As a result, water levels are often high enough for kayaking here when other rivers are too low. This is frequently the only place in Snowdonia, indeed in England and Wales, where kayakers can find sufficient flow to paddle white water of this quality and difficulty.
Currently, discharge in this section of the Conwy reaches or exceeds the minimum paddling threshold for 33% of the year. Since the hydro scheme will remove water from the river above the start of the run & return it below, discharge in the Conwy will have to be higher before flow in the Fairy Glen reaches the minimum level for kayaking. Initial calculations suggest that when this is accounted for, the Fairy Glen will run for only 19% of the year. This represents 42% drop in the amount of time when it is possible to paddle this section.
It could be suggested that diverting water might benefit kayakers by reducing levels in the Glen at times when the Conwy may be too high to paddle. It is important to realise however that this is not a gain in real terms. When the Glen is too high numerous other rivers of similar quality and difficulty are running so paddlers have numerous alternative options already. The greatest concern for paddlers in the loss of paddling on the Glen when it is the only section of this standard running, anywhere in England or Wales.