Installation of Onsite Ground Water Infiltration Basin

During the early stages of this project, it became evident that there was a high ground water level and this would massively effect programme and increase costs.

With the excavation of the pools that they were due to carry out, they were aware these excavations would quite quickly fill up with ground water which left them with two options available to them. Option 1 was to obtain relevant permits and pump ground water into the sewer network, Option 2 was to carry out investigations on site and check the feasibility of seeing if they could pump the water to another area of the site and let the water naturally percolate into the ground. The 1st option was extremely costly, time consuming (as we needed to obtain extraction permits from EA) and more polluting as larger diesel pumps were needed.

They carried out BRE365 infiltration test on the existing site and worked out the infiltration rate and deduced that they need at basin/pond capable of storing 1525m3 of ground water, this was incorporated into the works and was the first thing that was installed on site. They have been using electric pumps to pump water from excavations into the basin and the water in the basin has been percolating into the ground as per the initial concept.

This ensured the project started on time and that the client, which is a local authority, were not subject to increased cost which may have meant the project might not have gone ahead.