When you need an application
As soon as a project alters or uses a watercourse, the lower water authority is responsible. Typical cases: converting or removing a weir, building a fish pass or bypass channel, restoring a section, a stormwater retention basin, a discharge, a culvert or a bridge over the watercourse.
What belongs in the application
- Explanatory report describing the project and its effect.
- Site plan and sections based on a current survey.
- Hydraulic evidence: discharge, water surface profiles, proof that the flood conveyance is not made worse.
- Ecological effect, and for continuity also the functioning for the target species.
- Construction and programme concept – work on a watercourse is normally done at low water.
The procedure
- Survey and inventory Cross sections, bed levels, structures. Without exact bed levels there is no reliable water surface profile.
- Hydraulic calculation Determine the design discharge, calculate water surface profiles for low, mean and flood flow.
- Prepare the documents and pre-agree them with the authority – one preliminary meeting often saves a whole round of queries.
- Submission to the lower water authority.
- Consultation of the public bodies concerned: nature conservation, fisheries, heritage, neighbouring municipalities, depending on the case.
- Decision with conditions. Only then can construction start.
How long it takes
Our part takes a few weeks depending on scope. The authority's procedure typically takes several months – consulting the public bodies takes time, and queries extend it further.
Then there is the construction window: work on a watercourse is usually done in summer at low water. Whoever receives the decision in September builds the following year. So reckon on one to two years from idea to finished structure – and start early, especially where funding deadlines apply.
What shortens it
What helps most is having survey, hydraulics and application from one source. The most common delay we see arises at the handover: the surveyor recorded things differently from what the hydraulic engineer needs, and after the authority's query somebody has to go back into the field.