Concerns are mounting about the condition of rivers in the Yorkshire Dales as new figures revealed waterways in the national park considered to be in good ecological status had seen a significant decline.

A report to a meeting of the Yorkshire Dales National Park Authority on Tuesday states the condition of the protected area’s rivers, such as the Wharfe, Ure, Eden, Aire, Ribble and Swale, considered in good order dropped from 62 per cent to 51 per cent over the last three years.

The authority’s officers have highlighted how improving the condition of rivers is its sole priority objective where no progress is being made.

However, the Environment Agency river condition figures compare favourably to the national average of just 14 per cent being considered in good condition.

Park authority officers added they were awaiting further data on the reasons for the decline in quality, but have previously stated the largest sources of river pollution in the area are soil erosion, nitrates and phosphates from agriculture, and historical lead mine workings.

The authority’s meeting will be held hours before the Yorkshire Dales River Trust helps stage an event in Leyburn, which will be attended by Yorkshire Water’s river health improvement manager, to recruit “citizens’ science volunteers” to help identify and tackle issues in the Ure.

It follows 120 people who attended a Health of the River Ure meeting sponsored by the Association of Rural Communities expressing an is seeing such a group formed, with more than 35 willing to assist with water sampling from Appersett to Ripon.

Recent meetings have heard claims local planning authorities, and especially the Yorkshire Dales National Park Authority, should be more proactive in protecting the rivers from pollution.

A spokesperson for the group said: “There was considerable concern that the ageing treatment plants along the River Ure were already no longer able to cope with the amount of sewage and yet more housing estates and holiday lodge developments were being approved.

“There was concern about how the dairy industry has changed within the Dale with cattle kept indoors for much of the year, generating large amount of slurry that is spread on the flood plain and close to the river in huge quantities with obvious signs of green algae building up in the river this year already.

“The ploughing out of the biodiversity-rich wildflower meadows and planting with ryegrass has fundamentally changed the Ure catchment area and more needs to be done to encourage farmers to accept the impact they have on the river Ure and realise that those that work and manage the land are a vitally important to ensure the recovery of the river.”

The park authority’s natural environment champion, Mark Corner, said he was unclear what was behind the recent decline in river condition in the Dales.

He said: “I am frustrated that water quality isn’t improving and while water quality in the Dales is better than the national average, that’s cold comfort if the overall bar is low.

“We are promoting nature-friendly farming, which will reduce the number of inputs that farms are making, so there will be less slurry and fertilisers going into the rivers.”

Mr Corner said the authority was trying to do what it could as an enabler and facilitator and he hoped through the body’s management plan that “we are able to come up with more ambitious objectives and targets”.

He said: “It’s frustrating from an authority point of view in terms of the impact we can have on water quality. It’s other agencies that are mainly responsible for regulating and monitoring and investing.

“We can try and influence farming practices to keep nasty stuff like phosphates and nitrogen out of the rivers, but as an authority we have limited powers to do that. The only way we can directly influence this is through our planning committee.”