The valve tower, the stone structure at the end of the walkway, allows the flow of water from
NS4879 : Burncrooks Reservoir to be controlled. The tower extends vertically below water level, right down to, and through, the embankment of the reservoir, to meet a horizontal tunnel, by means of which water leaves the reservoir. The vertical tower contains a shaft; sluice valves there, controlled from the top of the valve tower, adjust the outflow of water:
NS4879 : Burncrooks Reservoir: outflow.
A small (though only compared to the valve tower) object can be seen out in the water, beyond the far end of the walkway; that device is shown, and its function explained, at
NS4879 : Floating mixer on Burncrooks Reservoir.