Chesham Waterside
Chesham Waterside is a long-term land and development project on a highly constrained site close to Chesham town centre. At the outset, the land faced an unusual concentration of barriers: contamination and fly-tipping, dense vegetation, Green Belt designation, Flood Zone 2 and 3 mapping, protected trees, nineteenth-century title restrictions, an adjoining watercourse and open questions over access and capacity. Rather than commit early to a single scheme, Cohanim has led a multidisciplinary strategy to investigate, remove and reduce each constraint while keeping the site's ultimate use open. The work spans site clearance, arboricultural and planning challenges, Upper Tribunal proceedings, hydraulic modelling of the River Chess, highways engagement, neighbourhood-plan representations, Grey Belt analysis, market testing and occupier negotiations.
Project team
The brief was not simply to design a building. The objective was to determine what this land could become, identify the matters suppressing its development potential and systematically improve its planning, technical, legal and commercial position. That required the architectural work to operate alongside planning policy, land law, arboriculture, flood engineering, highways, environmental analysis and commercial development advice. Crucially, the strategy has remained use-flexible. Independent feasibility work tested a range of potential development routes rather than assuming that the first concept generated for the site would necessarily represent its optimum long-term use.
A site constrained on paper from almost every direction The development challenge arose from the cumulative effect of several constraints rather than one overriding planning issue. The site was heavily overgrown and contained the legacy of former allotment activity, fly-tipping and historic industrial uses. It adjoins the River Chess and its tributaries and was shown partly within higher-risk flood zones on strategic Environment Agency mapping. It also lies within the Green Belt and within the influence of wider ecological designations. In addition, historic title documentation contained two nineteenth-century restrictive covenants associated with protecting the flow of water to a former mill. Although the purpose of those covenants had long since disappeared, they remained registered against the title and were capable of creating uncertainty over substantial future groundworks. The task became one of progressive de-risking: replacing broad assumptions about the land with evidence.
Recovering a neglected backland site
The two-acre site occupies an unusual position between established development, the railway and the River Chess, a chalk stream. It lies within walking distance of Chesham town centre and its Metropolitan Line station (TfL), with the London Underground line running directly adjacent to the site.
Prior to the current programme, the site had experienced decades of fragmented use and at one stage accommodated over 150 allotments. Historic industrial activity in the wider area, railway construction within the site itself and decades of fly-tipping had left substantial redundant structures, waste and contaminated material across the land - some of which was seeping into the adjacent chalk stream and required immediate remediation. A specialist clearance programme was therefore undertaken, including extensive vegetation removal and arboricultural clearance by PB Forestry. By 2025, the great majority of the initial clearance operation had been completed.
This was not simply cosmetic. Clearing the land allowed updated topographical, arboricultural and watercourse information to be obtained and made the physical characteristics of the site considerably easier to understand - facilitating accurate modelling and classification, which in turn informed the views reached by various parties.
The first significant intervention was physical rather than architectural. Large areas of uncontrolled vegetation, former allotment structures, waste and fly-tipped material were removed through a coordinated site-clearance programme. Specialist forestry contractors were employed for the principal vegetation works, with arboricultural input where required. The work changed the site from an inaccessible and heavily obscured parcel into land which could be properly surveyed, analysed and considered as a development opportunity, with substantial quantities of contaminated and redundant material removed from the land.
During the clearance programme Buckinghamshire Council imposed a blanket Area Tree Preservation Order across the site. Rather than accepting that designation as a permanent development constraint, we challenged the order using a pre-works tree survey, specialist arboricultural evidence and a tree-by-tree assessment. To ensure the Council had the capacity to deal with the case promptly, we asked to be invoiced for its Fast Track Advice Service, enabling the Tree Team to review our arboriculturists' reports and the temporary Area Order without delay and to dedicate the resources the case required. A friendly dialogue was opened and maintained with the tree officers throughout. On 25 July 2024 the Council formally decided not to confirm the blanket TPO, acknowledging the need to replace it with substantially more targeted protection. Following the subsequent arboricultural work, protection was reduced to the most significant trees around the perimeter and a single tree within the core of the site, enabling the wider site strategy to proceed while retaining the trees genuinely worthy of protection.
A second major constraint existed not in planning policy but in the land title. Two restrictive covenants dating from 1858 and 1860 sought to prevent works which might diminish the historic water supply to Lords Mill. The working mill had long ceased to exist and the former mill site had itself subsequently been redeveloped. Cohanim Architecture identified the opportunity to have the covenants removed and managed the process from start to finish. We prepared the evidence for an application under Section 84 of the Law of Property Act 1925, which required historical research into several sites across the town alongside the planning, title and architectural evidence needed to show that the original purpose of the covenants had become obsolete, and liaised with the Tribunal judge through to completion. On 6 August 2024 the Upper Tribunal (Lands Chamber) ordered both restrictions to be discharged wholly (ref. LC-2024-000288). No objections or claims for compensation had been made. The result removed a pair of 160-year-old restrictions from the title and materially improved certainty around future development, drainage and groundworks.
We worked with Dr Harvey J E Rodda BSc PhD FRGS and Artemis Venardos BSc to produce a comprehensive survey of the entire river network in the town, examining flow rates and water volumes and taking into account historic culverts and streams, natural springs and TfL boreholes to establish accurate flood data. This allowed us to provide our flood consultants, Herrington Consulting (now EPS), with accurate data, unlocking the potential to assess whether the nationally applied flood designation was accurate. Formerly the site was entirely within Flood Zones 2 and 3. We always knew this did not reflect reality. Following independent review, Environment Agency modelling and bespoke modelling, the site has now been almost entirely taken out of Flood Zone 3, with over two-thirds of it outside any flood zone. This means that - in conjunction with the other work - we have unlocked the majority of the site for safe development.
Highways feasibility was investigated separately rather than being left until a future full planning application. Transport work tested the ability of the existing site access and surrounding highway network to accommodate future development, including servicing, refuse movement, visibility and internal circulation. The subsequent highways pre-application process established a workable access strategy in principle and removed another of the principal uncertainties surrounding the site.
In the face of litigious legal teams, we researched and produced copious amounts of historic evidence and gradually pieced together a story which established a tapestry of information in the form of a cohesive evolution across the site - starting with 300+ year-old agricultural field surveys to subdivision by the Metropolitan Railway, to contemporary industrial development and through to various contemporary strands of information. This ultimately fortifies our client's legal arsenal to establish and maintain their rights in the course of contemporary negotiations.
The site has also been actively promoted through the plan-making system rather than relying exclusively on development management. Formal representations were made to the Chesham Neighbourhood Plan Regulation 16 consultation in November 2024, supported by planning analysis of the town's development needs and the site's role within the wider settlement. A detailed Vision Document was then prepared, bringing together planning, flood risk, transport, arboriculture and site evidence as part of the longer-term promotion strategy.
Changes to national Green Belt policy created a further opportunity to reconsider the site's planning status. The site had historically been treated simply as Green Belt land. Through successive pre-application discussions, comprehensive arguments which clarified existing non-permeable site boundary treatments such as mature foliage, streams and Common Land, presentation of planning evidence and analysis of its physical relationship with Chesham, a case was developed that the land does not strongly perform the purposes which Grey Belt policy is intended to protect. The position evolved considerably through 2025 and early 2026 as national policy, appeal decisions and case law developed, and continues to do so. Following further representations from the project team, Buckinghamshire Council's Principal Planning Officer confirmed in February 2026 that the application site could be considered Grey Belt, subject to compliance with the "Golden Rules".
Removing constraints before fixing the final use
Each of the constraints set out above was brought onto the radar, examined on its own merits and dealt with in turn. Taken together, they describe a single, deliberate strategy. Conventional development can begin with a brief and progress towards a planning application. Chesham required almost the reverse approach. Before committing the land to one particular solution, the project team concentrated on the matters which would constrain almost any viable form of development. The site was cleared. A blanket Tree Preservation Order was challenged and substantially reduced. Two obsolete nineteenth-century covenants were removed from the title through the Upper Tribunal. Detailed hydraulic modelling replaced broad flood mapping with site-specific evidence, and the majority of the site was successfully brought into Flood Zone 1. Access was tested through the highways pre-application process. The site was promoted in tandem through direct pre-application dialogue, a face-to-face meeting at Buckinghamshire Council's head office and the plan-making process, and its Grey Belt status was then addressed directly with the Local Planning Authority. Each step improved the land independently of any detailed design. The result is a development platform which is materially less constrained legally, environmentally and in planning terms, while retaining flexibility to respond to the most appropriate future use and market conditions. In all, dozens of constraints were identified, managed and mitigated in sequence, each one adding to the value of the land and its readiness for development. The work was carried out methodically and discreetly, and coordinated well beyond the usual remit of a multidisciplinary practice, let alone an architecture practice. Architecture and planning were brought together with arboriculture, flood engineering, highways, land law, topographical and watercourse surveying, ecology, contamination, market advice and wider planning policy, supported by an exceptional project team of consultants, legal advisers and specialists whose expertise and commitment have been central to the progress made.
From land strategy to a market-facing opportunity
The site has been deliberately tested against more than one development route. Independent development advice considered a range of possible uses and market sectors, allowing planning strategy and technical expenditure to be assessed against real-world demand rather than a purely theoretical masterplan. As the site's constraints have been progressively resolved, commercial discussions have advanced in parallel. Heads of Terms have now been agreed with a national company, demonstrating genuine occupier interest in the site and moving the project from strategic land promotion toward a market-backed development proposition.
A materially transformed development proposition
Chesham Waterside remains an active project. However, the property entering the current stage is substantially different from the land which began the process. It is clearer physically, less constrained arboriculturally, free from two obsolete restrictive covenants, supported by detailed flood modelling, tested from a highways perspective, promoted through the plan-making system and now supported by an express Local Planning Authority view that it is capable of being treated as Grey Belt subject to the remaining policy tests. Alongside this work, commercial engagement has established demonstrable market interest while allowing the final development solution to remain confidential and adaptable.
What the project delivered
Chronological summary
| Date | Matter | Achievement |
|---|---|---|
| 2023–Jan 2024 | Site investigation and clearance | Site surveyed and substantial clearance of overgrowth, former allotment infrastructure, waste and contaminated material commenced |
| Jan 2024 | Specialist clearance | Large-scale vegetation clearance progressed with PB Forestry and specialist arboricultural input |
| Jan 2024 | Tree Preservation Order | Blanket Area TPO imposed during the clearance programme |
| Mar 2024 | Independent feasibility | External development appraisal tested multiple potential market-facing uses for the approximately two-acre site |
| 24 Apr 2024 | Upper Tribunal application | Section 84 application made to discharge two obsolete nineteenth-century restrictive covenants |
| 25 Jul 2024 | TPO challenge | Buckinghamshire Council formally declined to confirm its blanket Area TPO and replaced it with substantially narrower protection |
| 6 Aug 2024 | Upper Tribunal – LC-2024-288 | Final Order issued wholly discharging both restrictive covenants |
| 2024 | Highways | Dedicated highways appraisal and pre-application work established a viable access and servicing strategy |
| Oct 2024 | First planning pre-application | Formal planning engagement tested the site's principal constraints and established the technical evidence required for the next stage |
| Nov 2024 | Chesham Neighbourhood Plan | Regulation 16 representations submitted on behalf of the landowner |
| Feb 2025 | Hydraulic model | Detailed numerical modelling of the River Chess and surrounding hydraulic network completed |
| 2025 | Flood strategy | Site-specific evidence demonstrated a materially smaller higher-risk flood extent than shown by strategic mapping |
| 2025 | Follow-on pre-application | Revised planning and technical evidence submitted following changes to national Green Belt policy |
| Feb 2026 | Grey Belt | Buckinghamshire Council confirmed that the site could be considered Grey Belt, subject to the remaining Footnote 7 tests |
| 2026 | Commercial strategy | Heads of Terms agreed with a national company |
| 2026–ongoing | Confidential development work | Further planning, technical and commercial engagement progressing while the detailed use and occupier strategy remains confidential |