SuDS and Drainage Design

No national law requires it, but development plans do. Kildare requires SuDS on all new development, down to a single house, and the Dublin councils require it through their plans and guides, so in practice it is part of almost every application.

The rate the site would drain at if it were still a field. Councils usually limit discharge from a development to it, worked out as QBAR with the IH124 method, with about 2 l/s/ha as the lowest rate a flow control can practically hold.

The first 5 mm of every rainfall, 10 mm preferred, held on the site so that it never reaches the drain or the river. It is the dirtiest part of a storm, and soaking it into the ground or the planting is what keeps it out of the watercourse.

Yes, wherever water is to be soaked into the ground. The test is done on the site to BRE 365, usually in the position of the soakaway, and the rate it gives decides whether infiltration works at all and how big the soakaway has to be. Councils commonly make it a condition of permission.

Only as a last resort. Kildare and South Dublin both ask for surface and nature based measures first, and a tank has to be justified by showing those cannot hold the water the site produces.

Uisce Éireann's answer to a pre connection enquiry, saying whether and how the development can connect to the water and wastewater networks. It usually takes around sixteen weeks and goes in with the planning application, so the enquiry is worth making early.

The owner or the management company, until the council takes the scheme in charge. A maintenance plan saying what is inspected, cleared and replaced, and how often, is commonly asked for with the application.