The posted coordinates take you to one of the spring pools that feed into the River Hamble, which form the main source of the river during the summer. The springs area located within the Moor Land Local Nature Reserve, which is a 34 ha area of hydrological sensitive environments. The area is a Site of Special Scientific Interest (SSSI) and a Nature Conservation Review (NCR).
These springs were under threat because of a local pumping station which dramatically lowered the local water table, which led to reduced water flow over many of the springs, and some areas drying up completely. Due to the areas awarding of SSSI and NCR status this pumping was stopped, and the flow rate has been restored.
The water from these boils are highly alkaline, which makes it ideal for growing watercress, which the area is well known for, especially Alresford. Due to this a number of watercress beds were operated on the Hamble, the last closing in the 1930's.
Despite their name, these natural springs are cold water that is forced to the surface because of the local geology. As the water is forced up through the river bed the sand and silt swirls around aiding the allusion that the water is boiling.
Springs are named for how they flow, and there are five main types. The first type of spring is a gravity spring. This is just what it sounds like - these form from the pull of gravity. The water gets pulled down through the ground until it reaches a layer it can't penetrate. Because it has nowhere else to go, it starts flowing horizontally until it reaches an opening and water comes out as a spring. These are usually found along hillsides and cliffs.
Next, we have artesian springs, which come from pressure in confined aquifers forcing the water to the surface. The pressure inside the confined aquifer (from being smooshed between those impermeable layers) is less than the pressure outside the aquifer, so the water moves in that direction. Any cracks or holes in the land will easily let the water escape.
Our next type of spring is a seepage spring, which as you may have guessed, is groundwater seeping out at the surface. Seepage springs slowly let water out through loose soil or rock and are often found in land depressions or low in valleys.
The fourth type of spring is a tubular spring. These springs occur in underground cave systems, which resemble underground highways. These tubes, or channels, are made of limestone, and as water moves through this type of rock, it dissolves some of it away. Tubular springs are some of the largest springs on Earth, and the tubes themselves can be so small that you can't see them or large enough to walk through!
Finally, we have fissure springs. Fissures are just large cracks, so you can probably figure out that fissure springs occur along large cracks in the ground, like fault lines. Fissure springs are often used as a source of drinking water, and sometimes scientists go looking for fissure springs when they want to find a fault on Earth.
To log this cache please email or message me the answer to these questions
1) The junction of what has caused the springs?
2) What is the chalky deposit formed by the alkaline water called?
3) Estimate the diameter of each of an induvidual 'sand boil'.
4) Using the descriptions given what type of spring are the sand boils?
5) Using the depth stick what is the depth of the spring pool?