The Harnham Water Meadows

The Harnham Water Meadows are probably the best known meadow irrigation system in England. Wessex in general is a very important county for water meadows and they form an important part of the historical landscape along with canals, mills, watercress beds and other engineered river-system features. A true water meadow is a pasture irrigation system that is irrigated at the discretion of the farmer and the specialist skilled worker who maintained and operated the meadows was called the ‘drowner’.  

The Harnham Water Meadows, located between west Harnham and Salisbury at the confluence of the Avon with the Nadder includes around 40ha of historic bedwork water meadows in various states of preservation on an island in the river system. The Trust owns or manages around 34ha of these. Around 4ha are irrigated during most winters and in recent years other areas are capable of being drowned but river levels are insufficient, some areas have lost their infrastructure and operate merely as flood meadows. There were water mills at Fisherton (for corn milling) and at West Harnham the ‘Old Mill’ was industrial. Originally river levels were controlled at both mills making watering of the meadows easier than today. The automated radial sluice gates by the Old Mill pub replaced an original structure.

The form of watermeadows at Harnham are called ‘bedworks’. Water is diverted from the river at a Main Hatch and flows in channels called ‘carriers’, eventually running along the tops of constructed ridges so that water trickles through the grass ideally at a depth of 25mm. It returns via a series of drains that feed a tail drain that returns the flow to the river. The job of the drowner is to maintain an even flow with irrigation events typically lasting for time periods between three days and one week.

‘Floated’ watermeadows are used for irrigation in the winter or early in spring to warm the grass sward and brings nutrients and oxygen into the soil. Typically this caused grass to start growing about one month earlier than un-floated floodplain meadows, so that animals could benefit from the ‘early bite’ of grass. Later in the season, during the summer when the soil was drying out, water meadows were re-watered so that (typically) two cuts of hay were taken and used to feed other animals – cattle and horses. 

Historically water meadows proved to be very important economically. Their construction and operation can be shown to date from the middle ages in both England and continental Europe, but their widespread adoption really occurred during the seventeenth century. Floated water meadows spread throughout Wessex, starting in Dorset in the 1600s and reaching the Wiltshire chalk valleys by the 1630s. There is no clear documented information describing the construction of the Harnham Water Meadows, but on circumstantial evidence it is believed to have been around 1660 when the meadow system was laid out on a pre-existing marshland landscape at the confluence of the Nadder and Avon.

In the eighteenth and early nineteenth centuries, ewes and lambs were led away from the meadow in the afternoon to fields of wheat or barley so their dung and urine would fertilise the arable land on the valley sides where they were ‘folded’ overnight. The system’s economic stimulus was corn price rather than sheep products - although these were an important by-product and the wool would have been used to manufacture textiles in Salisbury. This ‘Sheep-Corn’ system was of great importance during the period of the French Revolutionary and Napoleonic Wars when the country had to be as self-sufficient in food as possible. It is thought the hay crop was especially important at Harnham because it would have supplied coaching inns in the City.

A detailed enclosure map of West Harnham dates from 1787. It shows the two mills and meadow names suggesting a fragmented ownership pattern. The shape of the river channels is also remarkably similar to the modern day pointing to channel stability around the island upon which the meadows are located. This suggests there would have been an effort to maintain the status quo because of the functioning mills and meadows around Fisherton and West Harnham. 

Vulnerability of the Sheep-Corn system to economic downturn and technological change is demonstrated by factors such as labour costs, introduction of imported fertiliser as well as cheaper production of grain and lamb from north America and Australasia. This largely occurred after the recession in English agriculture in 1879. After this time, some water meadows would have been abandoned while others changed to alternative husbandry depending on market prices for milk, meat and hay. 

In the mid-19th century, the Earl of Pembroke made the last major changes to the Harnham Water Meadows; new carriers, hatches and aqueducts were formed using Victorian concrete, also small bridges over the channels to enable hay carts to be used to transport the hay off the meadow. The recession after 1879 meant that between 1880 and 1950 the number of sheep in Wiltshire dropped. Artificial fertilisers were introduced for arable land, farming was mechanised and many water meadows were gradually abandoned. At Harnham it is likely that only lower Seven Acres could be watered throughout the history of the meadows. Here, land sales, removal of hatches and possible shallow ploughing in some areas during the Second World War diminished the infrastructure that was designed for irrigation of the meadows. While anecdotal evidence suggests watering in places continued until the 1950s, the installation of the radial gates at West Harnham in the 1970s caused the overall river level to drop and over-abstraction reduced the volume of river water available for irrigation. In 1990 the Harnham Water Meadows Trust was formed to restore and preserve this internationally important heritage site and, where possible, increase the irrigated area of historic watermeadow.