Forestry: Much of the Tees Forest has been felled to make room for the built up areas along the river. This decreases the amount of interseption taking place and unnatural concrete surface speed up the flow of runoff into the river. The areas of forest left at river side intersept rain and slow it down, with some also entering the biomass store when the okats absorb the water.
Water Treatment: Northumbrian Water operates the Tees raw water system to supply major industrial users with large amounts of partially treated water. The system is the largest of its type in Europe and is capable of delivering up to 10m3/s (10 cubic metres per second). Water is abstracted from the River Tees via three pumping stations.
Water supply: In the Tees Valley the water quality is high, and so it is used as a water supply for homes and industry. The high rainfall in the area also gives a reliable water supply. There are several reservoirs in the river basin used to store water to be used for later use. The reservoirs also helps in flood control. Water levels can rise very quickly following a rain storm. Storing water in the reservoir reduces flooding in the lower course.
Farming and Irigation Water: A major land uses in the upper Tees is rough grazing for sheep. The land is too steep to use machinery, the growing season too short and the soils too thin and acidic For growing crops and so not much water is needed for irigation in comparison to the River Severn. Only where the land is less steep is the pasture improved by fertilizers, the occasional crop is grown, requiring some irigation water from the Tees.
Hydro Electric power: There are no power plants along the Tees.
There are also many natural factors affecting the hydrology of the River Tees drainage basin, these include:
Geology: There is a succession of falls, where the river traverses a hard series of black basaltic rocks, the water flows fast her due to the steep down slope, the impermiable smooth rocks also allow fast flow and no infiltration, and so at times of heavy percipitation the water level at these points in the river will rise sharply and the power and speed of the river will increase. At flatter areas of these basaltic rocks the river can flood easily.
Vegetation: The River Tees forest surrounds the River Tees, although parts of the forest nearer the river have been felled, the trees still intersept much of the rainfall that falls in the areas, intersepting percipitation before it reaches the ground. This water is stored for a while in the canopy of the trees as it takes time for water to gather in each leaf, fall to the next and so on, slowing the waters decent to the ground. The roots of trees also bring water up into the tree removing from the ground store, and this water then evaporates from the leaves, a process called transpiration. The canopy also provides shade keeping the ground cool, reducing evaporation. The trees and the roots are also a physical barrier slowing the movement of water. This all changes the amount of water entering the river and the speed at which it enters.
Relief: The head of the valley, of which the upper portion is known as Teesdale, has many hills, exceeding 2500 feet in height at some points, consisting of bleak moorland. Water will flow off of these hills into the river increasing the volume of water entering the river. This area has little vegetation further increasing the speed that the water enters the river. There are many areas of steep decents and so the are area with waterfall and rapids in the rivers. This means the water is travelling through the river at high speed and so has little time to infiltrate in surface into the ground store.
