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CGS Civils Consulting Civil Engineers offer a wide range of design and technical expertise and we are very capable of tailoring our services to suit your specific needs

drainage design


Using the latest design and modelling software along with adopting the most recent techniques from the SuDS manual (sustainable drainage systems), we can undertake both foul and surface water drainage design for any size development.


The drainage environment is current undergoing continuous change to combat flooding which is achieved in part by managing drainage at source. We have the necessary experience to carry out the drainage design to meet these stringent requirements whilst simultaneously providing a cost-effective drainage design.

All our designs will meet the criteria set out in Ciria C753, Building Regulations Document H and Sewers for Adoption 6th or 7th Edition. 

Flood Risk Assessment FRA


We can carry out Flood Risk Assessments for any scale development in accordance with the National Planning Policy Framework (NPPF), Local Authority requirements and Ciria C697. 

Where required, flood mitigation measures can be incorporated into the detailed drainage design. 

Planning drainage


At CGS Civils we specialise in clearing planning conditions and objections to secure planning approval with regards to drainage, flooding and highway matters. 

We can carry out any necessary testing such as winter soakage testing to BRE 365 and go on to immediately undertake the design work to include preparation of drawings and hydraulic drainage calculations which can be presented as a factual report that will satisfy the specific requirements of the local planning authority or Local Lead Flood Authority (LLFA)


We also specialise in preparing drainage strategy layouts and SuDS reports to support new planning applications.  



Utilising our state of the art 3D modelling software, we are able to generate Highway Designs, horizontal and vertical designs for carriageways, roundabouts and complex junctions.


Highway drainage can also be combined into this which enables us to produce detailed designs which can be scheduled for ease of approval or adoption and construction on site.

Consulting engineering


We can carry out both vertical and horizontal design of any site including the setting of finished floor levels, external levels and external finishes specifications including car park construction and porous surfaces.

section 38 section 278 agreements civil engineers


We can bring highway designs up to adoptable standards so that they can be adopted by the respective Highway Authority under Section 38/278 Agreements or under license.

Drainage design agreements west sussex


CGS Civils have the necessary expertise to undertake all drainage agreements with the respective water authority which include:

  • Section 104 Sewer Adoptions

  • Section 106 Sewer Connections

  • Section 98 Sewer Requisitions

  • Section 185 Sewer Diversion

soakaway test bre 365 soakage testing


We can undertake soil infiltration or percolation testing to the standard BRE 365 method or BS 6297 for discharge of treated effluent. This can either be by hand or machine excavated.

winter groundwater monitoring


Given the rise in the requirement for winter groundwater monitoring across many local authorities, we at CGS Civils have added this service to our skillset to enable us to provide a full suite of services to ensure compliance with these requirements. We have partnered with a trusted firm that can install the wells which will enable us to record the data which will feed directly into our drainage and SUDS designs. By keeping this service in-house we can provide a more cost effective service with a quicker turnaround than previous outsourcing

water neutrality


CGS Civils have the expertise to undertake both water neutrality reports and nutrient neutrality reports (nitrogen and phosphorus) in accordance with Natural England guidance to support any new planning application in any affected region. We will suggest modern techniques and technologies to ensure full water or nitrate neutrality to achieve planning approval, and to ensure that the impact to the local region is mitigated so that we aid the natural environment to support biodiversity and reduce the reliance on mains water.  

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