Technical insights and industry updates from our experts.
Stay informed with case studies, policy analysis, and practical guidance from Aegaea's flood risk and civil engineering specialists.
Recent insights from Aegaea
Buying a House in a Flood Zone: What You Need to Know
Considering buying a property in a flood zone? Here is a practical guide covering flood maps, insurance, surveys, mortgages, and how to protect your investment.
How to Discharge Drainage Conditions on Your Planning Permission
Drainage conditions on planning permissions can delay construction if not handled correctly. Here is a step-by-step guide to discharging them efficiently.
Flood Risk Assessment for House Extensions
When do you need a Flood Risk Assessment for a house extension? A practical guide covering planning requirements, flood zones, and what the FRA should include.
Flood Risk Assessment for Permitted Development
Permitted development rights do not exempt you from flood risk requirements. Here is when and why you still need a Flood Risk Assessment for PD schemes.
Flood Risk Assessment for New Build Homes
A comprehensive guide to Flood Risk Assessments for new residential developments, covering the Sequential Test, Exception Test, mitigation design, and planning approval.
Flood Risk Assessment for Change of Use Applications
Change of use applications often require a Flood Risk Assessment, especially when the new use is more vulnerable to flooding. Here is what developers and applicants need to know.
Flood Risk Assessment for Solar Farms and Renewables
Solar farms and renewable energy installations have unique flood risk requirements. Here is what developers need to know about FRAs, the Sequential Test, and design.
Flood Risk and Home Insurance: What You Need to Know
Understanding how flood risk affects your home insurance, the Flood Re scheme, and practical steps to secure affordable cover for properties in flood zones.
Flood Risk and Property Prices: What the Data Shows
How does flood risk affect property values? We examine the data on property prices in flood zones, insurance costs, and what buyers and sellers need to understand.
Foul Drainage Assessment (FDA1): When You Need One
The FDA1 foul drainage assessment form is a planning application requirement that catches many applicants off guard. Here is when you need one and how to complete it.
The Gladman Judgment: What It Means for the Sequential Test
The Gladman Developments v SSHCLG judgment reshaped how the Sequential Test for flood risk is applied. We examine the ruling and its practical implications.
How to Read the Flood Map for Planning
The Environment Agency's Flood Map for Planning is the starting point for any development in a flood-risk area. Here is how to read it correctly and avoid common mistakes.
Paved Gardens and Urban Flood Risk: The Hidden Problem
The paving of front gardens across the UK is a significant but often overlooked contributor to urban surface water flooding. Here is why it matters and what can be done.
SEPA vs Environment Agency: Key Differences for Developers
Developing in Scotland versus England means dealing with different flood risk regulators. Here are the key differences between SEPA and the Environment Agency.
SuDS Hierarchy Explained: A Developer's Guide
The SuDS hierarchy is fundamental to drainage design for planning applications. This guide explains each level, how to apply it, and common pitfalls to avoid.
What Is a Drainage Strategy? Everything You Need to Know
A drainage strategy is a fundamental requirement for almost every planning application. Here is what it covers, when you need one, and how to get it right.
Can I Write My Own Flood Risk Assessment?
Wondering if you can write your own FRA for a planning application? Technically yes for minor works — but here's what you need to know before you try.
Flood Risk Assessment for a Loft Conversion: Do You Need One?
Planning a loft conversion and been told you need a flood risk assessment? Here's when an FRA is required, what it covers, and how to get one.
Flood Risk Assessment for a Single Dwelling: What You Need to Know
Building a single house and need a flood risk assessment? Here's when one is required, what it should cover, and how to get planning approval in a flood zone.
How Long Does a Flood Risk Assessment Take?
Realistic timelines for flood risk assessments — from desktop studies to detailed FRAs with hydraulic modelling. What affects the timeline and how to avoid delays.
BRE365 Testing: What It Is and When You Need It
BRE365 infiltration testing determines whether your site can drain to ground. Here's how the test works, what the results mean, and the common mistakes we see.
Understanding Contaminated Land Planning Conditions
Contaminated land planning conditions follow a structured process from desk study to verification. Here's how to navigate each stage and discharge them efficiently.
The Drainage Hierarchy: Why Infiltration Testing Comes First
The drainage hierarchy dictates how surface water must be managed. Here's why infiltration testing is the critical first step and what LLFAs expect to see.
Road Safety Audits: What Developers Need to Know
Road Safety Audits are a mandatory part of most highway schemes. Here's what developers need to know about the four stages, who can carry them out, and what happens when problems are found.
Section 38 vs Section 278: What Developers Need to Know
Section 38 and Section 278 agreements are often confused but serve very different purposes. Here's how to tell which you need and what to expect.
When Do You Need a Phase 1 Desk Study?
Phase 1 desk studies are one of the most commonly conditioned planning requirements for brownfield sites. Here's when you need one and what happens if you skip it.
EA Climate Change Allowances 2026: What Changed and Why It Matters
The Environment Agency updated climate change allowances for flood risk. Here's what changed, which river basins are most affected, and how to apply the new guidance.
How Much Does a Flood Risk Assessment Cost in 2026?
FRA costs range from £750 for a simple desktop assessment to £15,000+ for complex modelling studies. Here's what drives the price.
Schedule 3 Wales: What Developers Need to Know in 2026
Schedule 3 made SuDS Approval Bodies mandatory in Wales. Here's what it means for developers, the application process, and common pitfalls.
Flood Risk Assessment for DataVita's North Lanarkshire UK AI Growth Zone
Aegaea collaborated with Woolgar Hunter Engineers to deliver a comprehensive FRA for the landmark DataVita AI Growth Zone in North Lanarkshire.
Timing is Everything: How Seasons Impact Your Flood Risk Survey (and Your Deadline)
Understanding how seasonality affects flood risk data collection, safety considerations, and project delivery timelines.
Do I Need a Flood Risk Assessment? A Quick Decision Guide
Not every development needs a flood risk assessment. Here's how to quickly determine whether your project triggers the NPPF requirement.
Desktop FRA vs Detailed FRA: When Do You Need Modelling?
Understanding the difference between a desktop flood risk assessment and a detailed FRA with hydraulic modelling — and when each is appropriate.
FRA Approval Process: Timeline and What to Expect
From instruction to planning approval — what happens at each stage of the flood risk assessment process and how long each step takes.
Can You Build in Flood Zone 3? Yes — Here's How
Flood Zone 3 doesn't mean your site is undevelopable. Here's how to navigate the Sequential Test, Exception Test, and mitigation to secure planning approval.
Flood Zone 1 with Surface Water Risk: Why It Still Matters
Your site is in Flood Zone 1 — great. But surface water mapping tells a different story. Here's why you might still need assessment and drainage design.
The SuDS Management Train: A Practical Design Walkthrough
The management train is the backbone of SuDS design. Here's how to apply it practically — from source control through to discharge.
Planning Appeals and Flood Risk: Lessons from Recent Decisions
Planning inspectors are scrutinising flood risk evidence more closely than ever. Here are the key lessons from recent appeal decisions.
SEPA Pluvial Flood Maps 2023 vs 2025
Scotland's flood mapping has undergone significant updates. We analyse the key differences between SEPA's 2023 and 2025 Surface Water and Small Watercourse Flood Maps.
How to Challenge EA Flood Mapping: A Step-by-Step Guide
EA flood maps are based on broad-scale modelling. If your site-specific evidence shows different risk, here's how to make the case for a map change.
Hydraulic Modelling - 3 Key Differences between Scotland and England
From LiDAR coverage to blockage requirements, understanding the regulatory differences is essential for cross-border projects.
TUFLOW vs HEC-RAS vs Flood Modeller: Which Software When?
Three industry-standard flood modelling packages, each with different strengths. Here's when to use TUFLOW, HEC-RAS, or Flood Modeller Pro.
Update on Water Neutrality and Water Efficiency in Sussex North Water Supply Zone (SNWSZ)
Water neutrality restrictions officially lifted in Sussex North, shifting focus from neutrality statements to 110 litres per person per day water efficiency standards.
Fife Council Flood & Drainage Updates 2025: Key Developer Changes
Fife Council published updated Design Guidance v3.0 on flooding and drainage, introducing a tiered system, updated climate change allowances, and new sensitive watercourses.
Changes to Planning Practice Guidance on Flood Risk and Coastal Change
The September 2025 PPG update brings meaningful flexibility for surface water-constrained sites. We explain what changed and what it means.
August 2025 Update to Environment Agency Flood Map for Planning (FMfP)
The EA introduces a new 'Flood Zones plus climate change' map layer, replacing the defended/undefended layers from the March 2025 update.
The Risk of Avoiding SuDS in Development
A recent appeal decision highlights the importance of following the SuDS hierarchy and providing evidence-based drainage strategies to avoid planning refusal.
Navigating Scotland's Surface Water Connection Policy: A Developer's Guide
Scottish Water's 'no new in, what's in out' policy requires developers to prove existing connections and achieve zero-net volumetric detriment before connecting to combined sewers.
Independent Water Commission Report 2025: Key Recommendations on Drainage, SuDS & Schedule 3
Sir Jon Cunliffe's Independent Water Commission recommends abolishing Ofwat, mandatory SuDS on all new developments, and commencing Schedule 3 across England.
How Dry Weather Increases Flood Risk in the UK
Long dry spells make soil hydrophobic and compacted, increasing surface water runoff and flash flooding risk when rain finally arrives.
Environment Agency EA2030 Strategy: Climate Resilience & Flood Risk
The EA2030 strategy sets out a five-year roadmap for tackling climate and nature emergencies, backed by almost £8 billion in flood investment over the next decade.
Flash Flooding in London Explained: Causes, Impacts and Solutions
Nearly a third of a million London properties are at high risk from surface water flooding. Understanding the causes, impacts and solutions for flash flooding in the capital.
National Standards for Sustainable Drainage Systems (SuDS) 2025
DEFRA launches refreshed non-statutory national standards for SuDS with seven formal standards, mandatory runoff hierarchy, and new requirements for amenity, biodiversity and whole-lifecycle design.
Flood Risk for Data Centres in Scotland
Scotland's data centre sector is expanding rapidly. Understanding NPF4 essential infrastructure flood risk requirements is critical for data centre developers.
Mid Sussex District Council Level 1 Strategic Flood Risk Assessment (SFRA)
Aegaea has completed a Strategic Flood Risk Assessment for Mid Sussex District Council, supporting climate-resilient development planning.
Over 1,000 New Flood Schemes Announced
The Government commits £2.65 billion over two years to fund over 1,000 flood defence projects, with every £1 spent saving approximately £8 in avoided damages.
SEPA Launches New Surface Water & Small Watercourse Flood Maps
SEPA releases new surface water and small watercourse flood mapping, covering smaller catchments under 3km2 with improved 2m resolution terrain data.
TAN15 Wales Flood Risk Policy Updates 31 March 2025
The Welsh Government releases the first update to TAN15 since 2004, introducing updated flood maps, revised zones, and stricter policies for development in flood risk areas.
Environment Agency Flood Maps for Planning (FMfP) Updates March 2025
The EA integrates NaFRA2 flood datasets into the Flood Map for Planning, with 6.3 million properties now identified at risk and new climate change projections.
Understanding the Growing Threat of Flooding: A Personal Perspective
A personal account of growing up in the flood-prone Calder Valley and how lived experience shapes professional understanding of flood risk.
Glasgow City Council: Bespoke Flood Risk Assessment and Design Requirements
Glasgow City Council has unique flood risk criteria beyond NPF4, including bespoke return period requirements and independent FRA certification.
Flood Risk and Surface Water Drainage in Enfield
Enfield has bespoke planning policies including level-for-level floodplain compensation and specific SuDS requirements for all developments including minor applications.
National Flood Risk Assessment 2 Update (NaFRA2)
NaFRA2 reveals 6.3 million properties at risk of flooding in England, with surface water affecting 43% more properties than previously assessed.
Dorset Council: Groundwater Drainage Guidance
Dorset Council requires 12 months of groundwater monitoring and infiltration testing for surface water drainage strategies, with a critical winter monitoring window.
Changes to the NPPF: SuDS Paragraph 182
The December 2024 NPPF update broadens SuDS requirements beyond major developments, requiring all applications that could affect drainage to incorporate sustainable drainage systems.
Changes to the Sequential Test - NPPF
The revised NPPF Paragraph 175 alongside new National Flood Risk Standing Advice changes the landscape for Sequential Test work, potentially unlocking more sites.
Everything You Need to Know About SuDS for Extensions and Small-Scale Developments
Local planning authorities are increasingly requiring SuDS for small-scale developments. Here's how to incorporate sustainable drainage into extensions cost-effectively.
Storm Bert and Property Flood Resilience
Storm Bert's extreme rainfall across the UK highlights the growing importance of Property Flood Resilience measures for homeowners in flood risk areas.
Flood Risk Policy in Royal Borough of Kensington and Chelsea
RBKC's 2024 Local Plan splits flood risk into two policies, extends FRA requirements to all basement development, and bans sleeping accommodation below ground in Flood Zone 3.
Flood Risk Assessment in Scotland: The Future Fluvial Flood Risk Area
SEPA's online flood maps underestimate the true Flood Risk Area due to outdated climate change allowances and missing structure blockage modelling.
Scotland Flood Risk and Essential Infrastructure
SEPA's updated Land Use Vulnerability guidance clarifies Essential Infrastructure definitions, potentially unlocking flood risk areas for renewable energy and BESS developments.
Aegaea Listed as Qualified Surveyor for Storm-Hit Properties in Leicestershire
Aegaea designated by Leicestershire County Council as a qualified surveyor for DEFRA property flood resilience repair grants following Storms Babet and Henk.
What Is Natural Flood Management (NFM)? Benefits & Funding
The Environment Agency announces £25 million in funding for Natural Flood Management, building on the pilot programme that supported 60 projects between 2017 and 2021.
What Are Property Flood Resilience Assessments?
Independent, accredited assessors should conduct property flood resilience assessments in accordance with the Code of Practice BS851188.
Flood Risk Updates in NPF4
NPF4 adoption brings major changes to Scotland's flood risk policy, requiring developments to be situated outside the Flood Risk Area including climate change allowances.
What Are Flood Warning & Evacuation Plans (FWEPs)?
Flood Warning and Evacuation Plans provide site-specific actions to reduce risk to life, mitigate damage, and enable safe evacuation during flood events.
SEPA Unveils New 3 Day Flood Forecast
SEPA and the Met Office launch the Scottish Flood Forecast service, providing 3-day advance notice of potential flooding impacts from rivers, surface water and the sea.
What is a Critical Drainage Area?
Critical Drainage Areas denote upstream catchments where mitigation measures could reduce flooding, but they are commonly misunderstood by developers and planners.
Updates to the Planning Practice Guidance (PPG) 25th August 2022
The largest overhaul of the PPG Flood Risk and Coastal Change since publication, changing everything from functional floodplain definitions to building lifetimes and sequential test requirements.
Updated Peak Rainfall Allowances: New Environment Agency Guidance on Climate Change Uplifts
The EA removes the standard 40% rainfall climate change uplift and implements regional variation by management catchment, with 48 catchments seeing increases.
SEPA Climate Change Allowances in Scotland
SEPA updates climate change allowances for peak flow and rainfall estimates across Scotland's 12 river basin regions, with the Tweed Basin seeing the largest increase to 59%.
London Borough of Sutton Local Flood Risk Policies
Sutton's Policy 32 requires flood risk assessment applicants to produce a SuDS strategy, with specific performance standards for greenfield and previously developed sites.
Flood Risk & SuDS Policy in Westminster
Westminster's City Plan Policy 35 addresses flood risk, vulnerable uses, flood management infrastructure, and sustainable drainage requirements for development in the capital.
Flood Risk Assessment: Independent Certifications in Scotland
Many Scottish councils now require independent third-party certification for Flood Risk Assessments and Surface Water Drainage Strategies as part of planning applications.
Flood Hydrology Roadmap: UK Vision for the Next 25 Years
The Environment Agency has unveiled a 25-year roadmap with £165 million allocated to enhance hydrological methodologies through 31 coordinated actions.
Understanding the Economic Impacts of Flooding and Risk Modelling
How flood risk modelling informs economic assessments of flood defence schemes, from depth-damage relationships to Annual Average Damage calculations.
Are Flood Risk Assessments in London Different From Other Parts of the UK?
London's flood risk assessments differ substantially from other UK regions due to the Thames Barrier, breach mapping, and 32 borough-specific planning requirements.
West London SFRA: Essential Flood Risk Assessment Guidance
Six West London boroughs operate under a distinctive SFRA that places surface water flooding on equal footing with river and tidal flooding, with unique compensatory storage requirements.
SEPA's Position on Elevated Buildings in Flood Risk Areas
SEPA guidance on elevated development using pillars or stilts in flood risk areas, covering brownfield requirements, height standards, floodplain impact and safe access.
RBWM Local Plan Update: Key Changes to Flood Policy
The Royal Borough of Windsor and Maidenhead replaces Policy F1 with NR1, removing the long-standing 30-square-metre extension threshold for flood risk assessment requirements.
Surface Water Drainage in Scotland: What Developers Need to Know
Scottish Water requires developers to follow a five-tier drainage hierarchy before connecting to the public sewer network, with robust evidence needed to justify lower-tier options.
Aegaea on ITV News: Tower Bridge Flooding Investigation
When surface water flooding affected Tower Bridge, ITV News London engaged Aegaea to investigate the causes and explain potential prevention measures.
How the Flood Map for Planning Affects Development
The Flood Map for Planning is a screening tool that determines whether development proposals require a Flood Risk Assessment, dividing land into three flood zone categories.
What Is a Sustainable Drainage System (SuDS)?
A technical overview of Sustainable Drainage Systems: what they are, why they matter for planning, and how they mimic natural catchment responses to rainfall.
Updates to Climate Change Allowances in England, July 2021
The Environment Agency revised climate change guidance for river flows, replacing broad regional approaches with granular management catchment boundaries based on UKCP18.
Changes to Chapter 14 of the NPPF: Flood Risk Updates July 2021
The July 2021 NPPF updates expanded flood risk assessment to cover all sources of flooding, broadened the sequential test, and added emphasis on property flood resilience.
What Are the Sequential and Exception Tests?
The sequential and exception tests guide development toward the lowest flood risk locations, comparing sites and enabling development where justified through wider sustainability benefits.
What Is a Flood Risk Assessment? And What Do All the Flood Zones Mean?
A guide to Flood Risk Assessments in the planning system, covering when they are required, how the four EA flood zones work, and vulnerability classifications.
Do I Need a Flood Risk Assessment for a Major Development?
Major developments always require a Flood Risk Assessment and Drainage Strategy. Understanding the thresholds and requirements early saves time and money.
The Pitt Review: Lessons from the 2007 UK Flooding Crisis
How the 2007 UK floods led to the Pitt Review, establishing Lead Local Flood Authorities and reshaping national flood risk policy for a generation.
What Is a Lead Local Flood Authority (LLFA)?
Lead Local Flood Authorities manage surface water, groundwater and ordinary watercourse flooding, serving as key planning consultees for SuDS and drainage strategies.
How Climate Change Updates Affect Peak River Flows and Flood Planning
The Environment Agency moved from a blanket 20% climate change allowance to a River Basin Districts approach, with allowances varying significantly by location and development type.
What Impact Does the Revised Breach Model Have on London Flood Risk Assessments?
The 2017 update to the Thames Breach Model expanded from 113 to 5,679 breach locations, significantly changing residual flood risk assessments across central London.
What Is a Flood Risk Assessment? How to Make It Work
A Flood Risk Assessment evaluates flood risks to a development site and determines mitigation measures. A properly executed FRA can streamline planning and maximise development potential.
Changes to the London Plan and How It Will Affect Flood Risk
The London Plan 2019-2041 introduces Policies SL12 and SL13, evolving flood risk management and sustainable drainage requirements for development across the capital.