Water Services

  • Water services

Water Services Consultants

Flood Risk Assessment, Environmental Statement, Drainage, Surface Water Assessment, Economic Assessment

Our principal aim is to support our developer clients during the planning process, and our corporate and investor clients by assessing risk from all sources of flooding, as well as providing due diligence and technical advice on flood risk including mitigation measures and residual risks. Our team of specialists have worked across a variety of project sectors including housing and regeneration, retail, energy, industrial and waste and agriculture and food, providing high quality advice and cost-effective flood risk and drainage solutions to meet the needs of our public and private sector Clients.

Services we offer

Flood Risk Assessment

We undertake Flood Risk Assessments (FRAs) to determine site-specific flood risks from all sources of flooding, ranging from:

  • Tidal
  • Fluvial (main river and ordinary watercourses)
  • Surface water
  • Groundwater
  • Artificial drainage (reservoirs, sewers and canals)

We determine the receptors at risk, the potential mitigation measures and residual risks to ensure the development or investment is safe from flooding, without exacerbating risk in the locality or downstream.  Flood Risk Assessments can be implemented if your site is within a Flood Zone or greater than one hectare in size; we can offer services in a staged approach from a basic FRA through to standard or more detailed FRA, including hydrology and hydraulic modelling though our esteemed associates, depending on the site and the level of detail required.

We also offer FRAs and Emergency Response Plans for due diligence purposes, largely working with our ETS colleagues. With any land, property, purchase or disposal it is vital to undertake a range of due diligence checks to prevent the discovery of any unforeseen obstacles further into the process.  We support and advise our clients to future-proof the assets and portfolios, considering current and future flood risks due to climatic change predictions and recommending appropriate mitigation measures, resilience measures and high-level costings.


It is becoming increasingly important to demonstrate to statutory consultees that surface water drainage has been considered as part of the development process. A Drainage Strategy is a report which determines how surface water which enters the site (usually as rain) will be managed so that it does not exacerbate flood risk elsewhere.

The Drainage Strategy should assess and advise on the most appropriate drainage solutions for the Site. Developments should utilise Sustainable Drainage Systems (SuDS) unless there are practical reasons for not doing so. For many sites a Drainage Strategy has become a validation requirement, in Wales, Schedule 3 of the Flood & Water Management Act, now requires new development to have SuDS approval in conjunction with (but separate to) the planning process.

Delta-Simons can provide a complete drainage package from outline planning through to detailed design, utilising trusted partners where required.

Ideally surface water should be managed as close to its source as possible, soakaways are high on the “drainage hierarchy” and the preferred option.  Many Local Planning Authorities request confirmation at planning stage of the viability of soakaways as part of the surface water management scheme. Delta-Simons can provide soakaway testing to inform this and the drainage design.

Environmental Statement

FRAs and Drainage Strategies can be used as an annex to an Environmental Statement (ES) as part of the EIA process. In addition, we can complete the Water Environment ES Chapter including water quality fundamentals such as Highways Agency Risk Assessment Tool (HAWRAT) routine runoff and spillage risk assessments, working with our geo-environmental team to deliver the groundwater components to provide a complete water services package. 

Our ES Chapters identify and assess the sensitivity of receptors, the potential magnitude of impact and the potential significance of effect of the proposed development during the construction and operational phases.  We identify appropriate mitigation measures to offset the potential significant effects, detail the residual risks post-mitigation and the inter-topic and third party cumulative effects to overall ensure a negligible effect on the Water Environment.  We have wide-ranging experience completing ES Chapters for a range of Clients and schemes ranging from residential developments through to poultry farms and road schemes.

Surface Water Assessment

We undertake surface water assessments, typically working with Lead Local Flood Authorities (LLFA) to complete a prioritisation matrix-style assessment to rank the surface water hotspots based on key criteria such as:

  • records of historic flooding
  • risk of surface water flood extents
  • critical infrastructure (e.g. road, rail, schools)
  • development sites (e.g. Strategic Housing Land Availability Assessment (SHLAA) and Employment Land Review (ELR)

Weightings can be added and the matrix tailored to your specification in order to best represent the areas for further assessment, such as problem definition or optioneering.  Our team of specialists can complete additional reports for each prioritised hotspot to further understand the flood risk mechanisms, and to highlight potential options or mitigation measures to take forward to economic assessment.   

Economic Assessment

We offer our clients a complete solution to surface water risk by providing an Economic Assessment service, calculating the baseline economic damages for residential and commercial properties, short-listing a range of options and calculating each option’s benefit-cost ratio to determine the most viable and cost-effective options to mitigate the risk.


For more on all our Water Services, contact Alex Perryman.