The availability of water would have been a primary reason for early settlement in this area. The River Gade is a chalk stream. It is a tributary of the Colne and eventually feeds into the Grand Union Canal.
The river gathers rain water that has soaked through the chalk. It becomes alkaline and rich in nutrients and is cooled by its journey through the chalk to emerge at a constant temperature of 56 degrees, regardless of summer heat or winter freezing.
The river provides a perfect gentle habitat in which everything grows abundantly, insects, water plants, fish, birds and mammals. Maybe this was why a Little Egret was seen here on one especially bleak winter.
Rocky ridges in the riverbed cause little waterfalls and natural places where the river could be dammed for mill runs and for the watercress beds, traces of which can still be seen on an 1898 map.
I had assumed that these ridges were man made weirs of some sort connected with the watercress beds because clay and chalk would not be hard enough. Could these be caused by the presence of a layer of Greensand in the Gade valley?
Watercress, which is very rich in iron, tasty, peppery and crisp has been grown in the Gade commercially for centuries, with great amounts paked and sent for the London market. Harvesting watercress was cold wet and tiring work.
The Dacorum Borough Council has shown respect for the Gade as a chalk stream by purposely keeping the river that runs through the Riverside shopping area of Hemel Hempstead in its wild state and only mowing the higher banks. You can contrast this with the earlier Water Gardens when it was channelled in cement.
In times of low rainfall it can dry up and many chalk streams are now considered to be on the edge of extinction due to extraction for agriculture and housing.
At the highest points above Grovehill there is about 18" of soil, built up from dead vegetable matter from various sources, 6-10 foot of clay, and chalk underneath down to the level of the Gade, about 300ft above sea level.
The Gade remains at 56 degrees regardless of summer heat or winter freezing.
The chalk is porus and acts like a sponge, holding the water from just running off, and aquifers are formed, underground lakes and this is what is 'tapped' into for the wells.
Although earlier people would have stored rain water and taken their water from ponds like Cox's Pond, wells have been dug in the chalk for hundreds of years if not even much longer. Wells around Grovehill are about 130-160ft deep. Digging deep into chalk is a skill that goes right back at least to the Stone Age when the chalk was mined for flints as at Grimms Graves. A chalk mine in Hemel, possibly Anglo Saxon, was recently discovered when it collapsed.
A local farmer recalls the especially dry summer of 1921 when the water table sank below the bottom level of the wells and water had to be brought in by tanker.
In the mid thirties the wells had to be dug deeper, 200 ft and 2" bore pipes were put in.
Early wells were operated by dropping a bucket in and winding a handle manually to pull it up or by a horse walking round and round to wind it up.
There were two rainwater tanks at St Agnells Farm, one for water for the animals
and one for the house used this very soft water for washing clothes and bodies.
Around 1880 Shadrach Godwin purchased a three flow water pump made by Davis and Bailey at their Boxmoor Iron Works (where Bank Court is now). This gave a continuous flow of water and so was more economical than previous pumps and was installed at St Agnells Farm to provide water for the farm and local houses.
Initially he also had it piped into a tank for general use where is often froze, but in 1934 a local farmer found that by installing his tank over the stable and insulating it with straw it was kept warm by the horses and never froze, even in the coldest winters.
With the New Town a greatly increased demand was made for water and so much water was drawn that the natural level of the water table dropped.
In 1939 a new main water pumping station was built on the other side of the Leighton Buzzard Road.
Some of the Willows which grew along the banks of the Gade were Cricket Bat Willows, the wood springy and resllient.
THE RIVER GADE, URBAN TREATMENT OF A CHALK STREAM