The principal watercourses of the area are, the Stevenage Brook, the Aston Brook, and the River Beane. 

The Stevenage Brook rises near Whitney Wood, and flows south, joining the River Beane at Watton at Stone, which in turn joins the River Lea at Hertford, with the Lea eventually flowing into the Thames at Bow in East London. The Brook is now a culverted stream, which only becomes visible when it emerges from its underground journey in Monks Wood Way. In former times the Brook flowed through the High Street as a rivulet linking several ponds. The Brook in the High Street was culverted around 1850. The ponds, of which there were 20, were in the Seventeenth, Eighteenth, and early Nineteenth Centuries important to the Drovers from the north who drove their livestock down to the market at Smithfield in London, using Stevenage as a stop-over to feed and water their animals. In 1933 the last of the ponds, Weir Pond, opposite Holy Trinity Church, was filled in. From the High Street the Brook flowed through Ditchmore Common (now part of King George’s Playing Fields), where it was known as, “the ditch”, along what is now St. George’s Way and under Bedwell Lane at The Town Centre Gardens. The flow into the Brook, prior to its alignment and further culverting by the Stevenage Development Corporation, was made up from surface water, two sewers draining the Old Town area, some natural springs, two tributaries, the overflow from the railway troughs at Langley Sidings (these were troughs of water which were scooped up by Express Steam Trains without the need to stop to take on water), and the effluent and storm water overflow from Sewage Works at the Roaring Meg and at Knebworth. Sixty per cent of the Brooks flow was treated sewage effluent. Also in former times when the Brook reached Broadwater it used to become swollen with water draining down from higher ground, and spreading out across marshy land, this area is marked on old Ordnance Survey Maps as, “liable to flood”.

Aston Brook rises at Aston End and flows behind Edmonds Drive and beside Gresley Way, joining the Stevenage Brook at Bragbury End. Like the Stevenage Brook, the Aston Brook has been straightened, and in places culverted. 

Part of the River Beane forms the eastern boundary of the parish of Aston. In recent years as a result of water abstraction, and the flow having ceased from some of the springs in its upper reaches, this section of the Beane is often dry.

Because of the limited capacity of the Stevenage and Aston Brooks, and to prevent flooding elsewhere in the town at times of storm, the Stevenage Development Corporation created a series of water meadows. Such meadows exist at, Corey’s Mill, Burymead, Symonds Green (now sadly overgrown), Elder Way, Wychdell, and Ridlins End. These meadows have become beneficial to wildlife.

In addition to the former ponds in the High Street, Stevenage in the past had many other ponds, some of which still survive. Most of these were Farm Ponds such as those that still exist at The Towers in the Town Centre, Symonds Green and Chells Manor, other small ponds existed in fields before the development of the town, either naturally in marshy areas, such as the two on the site of Bude Crescent in Symonds Green, or as artificially created dew ponds, such as the one on the site of Dew Pond Close in the Old Town. The pond at the Town Centre Gardens in St George’s Way was formed from an area of marshy ground fed by a natural spring known as, “Bedwell Plash”. Aston still has its village pond, Whitney Pond.

In addition to ponds there were in the eighteenth and nineteenth century small flooded clay pits at Fishers Green and in the Brick Kiln Road area. These were the result of clay extraction for brick making. The last of these former pits, which existed beside the railway at Brick Kiln Road, and which was rich in wildlife, was filled in when a sewer pipe was laid in 1967.