1 By Caitlin Ryan

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3 The River Gade n The River Gade is a chalk stream that rises from a spring in the Chiltern Hills. n It’s a shallow river. n It’s named after the village of Great Gaddesden (where it begins).

4 Chalk Streams and Aquifer n The River Gade is a chalk stream with very clear water. Chalk streams are globally rare, which makes the River Gade even more special. n Chalk streams are fed from groundwater. This water is stored in an aquifer. n An aquifer contains layers of chalk that soak up rainwater like a sponge. At various points the water emerges as springs, which feed the streams.

5 Aquifer process n This process through the chalk allows the water to gather nutrients (useful for plant life) and is cooled by it’s journey through the chalk to emerge at a constant temperature regardless of summer or winter.

6 Map of River Gade

7 The River’s Journey n The River Gade travels almost entirely through Hertfordshire. n The river begins it’s journey from the springs in Great Gaddesden. n It travels through Hemel Hempstead, Kings Langley and Croxley Green to Rickmansworth. n Finally it joins the River Colne and The Grand Union Canal. n Later joining the River Thames.

8 Pressures on the River n In the past couple of years many chalk streams have been on the verge of extinction due to a lack of rain. Thankfully the recent wet weather has saved chalk streams.

9 Building n The River Gade suffered problems during the building of Hemel Hempstead’s new town after World War 2. n The demand for water increased. n High levels of water were drawn. n The natural water table level dropped causing a drop in the river depth.

10 Features of the River Gade

11 Upper Course n Source - Spring at Great Gaddesden n Small stream n V-shaped Valley - “High Gade Valley” n Waterfalls - Rocky ridges in the riverbed cause little waterfalls.

12 Middle Course n Floodplain - “Hemel Hempstead” n Erosion - Meander about to meet to make an oxbow lake near Croxley Green

13 Lower course n Large floodplain - near Rickmansworth n Wide smooth channel

14 Wildlife n The River Gade is very important to wildlife. Including many species that are rare and come from different countries. A little egret was seen here on one especially bleak winter. n The meadows support a diverse community of birds. Such as finches, thrushes, waders and a wildfowl during winter and other birds breed on the meadows in the summer.

15 History n The River Gade has attracted people for centuries to live, work and enjoy the countryside in it’s beautiful valley. n The Romans created a settlement in the area now occupied by Gadebridge Park. n The River provided a source of power for a corn mill at Water End. n Watercress used to be grown for the London market. Traces of the old watercress beds can still be seen from Google Earth.

16 Quiz? n What’s the name of the village where the River Gade begins? n Answer:Great Gaddesden n Where does an aquifer collect it’s water from? n Answer:The Rain n Name all four of the towns and villages the River Gade travels through? n Answer:Kings Langley, Hemel Hempstead, Croxley Green and Rickmansworth. n What’s the name of the rare bird spotted by the River Gade? n Answer:Little Egret