From Mardale Head a clear and sinuous path climbs across rough pasture and open fell towards Small Water, the lesser-known sister tarn to Blea Water in the neighbouring hanging valley. The ascent is steady rather than severe, and the line of the path naturally follows the glacial contours that lead into the suspended corrie beneath Harter Fell. As height is gained, the geometry of the valley becomes increasingly apparent, with Haweswater stretching behind and the corrie headwall slowly enclosing the route ahead.

The imposing slopes and broken crags of Dudderwick dominate the northern side of the valley at the commencement of the ascent from Mardale Head. Their steep faces frame the entrance to the hanging valley leading towards Small Water, before easing in height as the skyline opens to reveal the well-trodden ridge from The Rigg to High Street. At its far eastern end stands Riggindale Crag, historically significant as the site of the last known golden eagle eyrie in England, the final female disappearing in 2004.

The route to Small Water passes just south of the area known as Mardale Waters, a wide upland catchment lying beneath Blea Water and its enclosing corrie. The steep back wall of that corrie is formed by the eastern slopes of High Street, whose Roman road alignment crowns the skyline above. Blea Water Beck issues from the tarn and descends through rough fellside before merging with Small Water Beck, the combined waters ultimately draining into Haweswater Reservoir below Mardale Head.

As the ascent steepens around the lower crags of Harter Fell, a striking view opens across the valley floor. Blea Water Beck, issuing from its high corrie beneath High Street, descends in a series of bright cascades to the left, while Small Water Beck tumbles more directly from the hanging valley ahead. The two watercourses run briefly in parallel before uniting further downstream, their confluence marking the combined drainage of the twin corries into Haweswater Reservoir.

Looking back along the valley towards Mardale Head reveals the point at which Blea Water Beck and Small Water Beck have merged, forming Mardale Beck as it continues eastwards towards Haweswater. The combined flow drains the twin hanging valleys beneath High Street and Harter Fell, funnelling their waters into the main reservoir below. This view of Haweswater, photographed in 2021, shows the reservoir at its lowest recorded level in more than two decades, exposing the underlying valley form normally concealed beneath the waterline.

Small Water Beck falls steadily from the tarn in a continuous chain of small waterfalls and broken cascades, cutting through the steep-sided hanging valley beneath Harter Fell. Although none of the individual drops are high, their frequency and clarity give the beck a lively character, particularly as the gradient sharpens closer to the corrie basin. As the valley floor widens lower down, the watercourse begins to level and braid across the rough ground before joining Blea Water Beck further downstream.

Small Water Tarn occupies a classic glacial corrie at the head of one of the twin hanging valleys that descend towards Mardale. The back wall and eastern rim of the corrie are formed by the rising slopes of Harter Fell, while its northern boundary is defined by Piot Crag, which separates Small Water from the adjacent basin of Blea Water. From the rear of the tarn, Nant Bield Pass climbs steadily towards a narrow arête dividing Mardale from Kentmere. From this high ridge, paths branch towards Harter Fell, Mardale Ill Bell, and Kentmere Pike, making Small Water an important junction within the eastern Lake District fells.

Small Water Tarn is fed by three distinct gills descending from the steep corrie slopes of Harter Fell, together with a fourth watercourse draining from the crags of Piot Crag to the north. These short but lively inflows sustain the tarn throughout the year, particularly after periods of rainfall. The outflow emerges from the north-east shore, forming the headwaters of Small Water Beck as it begins its descent through the hanging valley towards Mardale Head and Haweswater.

Along the western shore of Small Water Tarn are several small stone shelters linked to the historic packhorse route over Nant Bield Pass. The pass once served as an important trading connection between Mardale and Kentmere, and these rough structures offered emergency refuge to travellers caught in deteriorating conditions. They are extremely low and narrow — more crawl-space than hut — but in exposed weather on the high fells even such minimal shelter can provide valuable protection from wind and driving rain.