River Teise Flooding & Flood Risk

The River Teise is a small Wealden river with a long history of putting Kent villages under water. It drains a band of heavy clay in the High Weald above Tunbridge Wells, and because clay sheds rain rather than soaking it up, the Teise rises quickly and spills onto the low ground at Lamberhurst, Goudhurst and Marden after wet weather. Where it joins the River Medway and the River Beult at Yalding it helps make that village one of the most flood-prone places in England. Unda prepares flood risk assessments, drainage strategies and related reports for sites across the River Teise floodplain. To talk a site through, call 01293 214444 or email enquiries@unda.co.uk.

At the Stonebridge gauge near Horsmonden the Teise reached its highest recorded level — 3.40 metres — during the great October 2000 floods, more than a metre and a half above its usual top-of-range, and the same run of storms began the wettest chapter in the river’s modern flood record.

• A flashy clay river. The Teise drains the impermeable Weald clay of the High Weald, so runoff reaches the channel fast and levels peak sharply after prolonged or heavy rain.
• A designated Main River. The Environment Agency regulates the Teise through its middle and lower reaches, so the 8 metre byelaw margin and Flood Risk Activity Permits apply to work near it.
• Three live Environment Agency gauges. Bartley Mill near Wadhurst, Lamberhurst and Stonebridge near Horsmonden all appear on the map below, with their latest levels updating in real time.
• It splits before it reaches the Medway. South-west of Marden the river divides into the Greater Teise, which joins the Medway at Twyford Bridge above Yalding, and the Lesser Teise, which runs to the River Beult at Hunton.

Check flood risk along the River Teise

The map below draws the River Teise in coral, with the Environment Agency’s live river gauges positioned along it — click any gauge to see its latest level, its typical range and its record peak. Enter a postcode near the river to zoom in and screen that location against the Environment Agency’s flood data for rivers and sea, surface water, reservoirs and the flood zones used for planning. It is an indicative screening tool, not a flood risk assessment.

Why does the River Teise flood?

The Teise floods because of the ground it drains. Its catchment is cut into the heavy clays and thin sandstones of the High Weald, and clay does not absorb rain — it sheds it. When wet weather sets in, water runs off the fields, woods and lanes into the channel far faster than it would over chalk or sand, so the river fills quickly, peaks sharply and then falls away. Hydrologists call a river that behaves this way “flashy”, and the Teise is a textbook Wealden example: quiet for much of the year, then capable of rising more than a metre in a day once the ground is saturated.

The river rises in the wooded country above Tunbridge Wells, gathering the flow of the parkland lakes around Dunorlan and Bayham before running east through Lamberhurst. A little below the village it is joined by the River Bewl, which drains Bewl Water — the largest area of open water in south-east England — and the reservoir’s compensation releases help sustain the Teise through dry spells. From there the river winds past Goudhurst and Horsmonden and out across the low farmland toward Marden, where it divides. The Greater Teise carries the main flow north to meet the River Medway at Twyford Bridge, just above Yalding; the Lesser Teise branches off to join the River Beult at Hunton. That split matters in a flood, because the same river can push water into two different valleys at once.

• A clay catchment that sheds rain. Impermeable Weald clay across the catchment produces rapid runoff and a fast-rising river after prolonged or intense rainfall.
• A reservoir at its head. The River Bewl, dammed to form Bewl Water, joins the Teise below Lamberhurst; the reservoir stores winter water pumped from the Medway at Yalding and releases compensation flow back to the Teise in summer.
• Three gauged reaches. The Environment Agency records levels at Bartley Mill in the upper valley, at Lamberhurst, and at Stonebridge near Horsmonden — the reaches where flooding is most closely watched.
• It empties into rivers already under pressure. Both arms of the Teise reach the Medway and the Beult around Yalding, so its peak can arrive when those larger rivers are already high.

A history of flooding on the River Teise

The Teise sits within one of the most flood-prone corners of Kent, and its record runs deep. The communities along the Medway and its tributaries — the Teise among them — have been hit repeatedly, with major floods recorded in 1960, 1963, 1968, 1974, 1979, 2000/01 and again in the winter of 2013/14. The October 2000 storms drove the Teise to its highest recorded level at Stonebridge, 3.40 metres, on 12 October that year.

The benchmark modern event came over Christmas 2013. When Cyclone Dirk crossed southern England on 23–27 December, it fell on already-saturated ground and produced the largest flood measured in much of the Medway catchment. More than 900 homes and businesses were flooded across Tonbridge, Maidstone, Yalding, East Peckham and smaller communities as the Medway and its tributaries came out of bank, and the Leigh flood storage area upstream of Tonbridge, though it did its job, was overwhelmed by a flow bigger than it was built to hold. At Yalding, where the Teise and the Beult meet the Medway, homes were left under water for days over the holiday. The Environment Agency estimates that more than 3,000 homes and businesses in Tonbridge, Hildenborough, Yalding and Collier Street are at risk from the combined flows of the Medway, the Beult and the Teise.

These are the events an assessment for a nearby site has to reckon with. A history of flooding also has to be declared when a property changes hands, which is one reason a site-specific report matters — see our note on flood history declarations when selling a property.

Which areas does the River Teise put at risk?

Flooding from the Teise is concentrated on the low ground of the valley floor, and the Environment Agency runs a formal warning service for the communities most exposed. Three flood warning areas name the river directly: the River Teise in Lamberhurst and Goudhurst; the River Beult and Lesser Teise at Collier Street, covering Marden, Benover, Chainhurst and Haviker Street; and the River Medway, River Teise and River Beult at Yalding. The table below summarises the main settlements at risk from source to mouth.

If your site sits within one of these areas, the Environment Agency’s flood map for planning is likely to place it in Flood Zone 2 or 3, which triggers the need for a site-specific flood risk assessment. You can screen any address against the live Environment Agency data using the map above, and the towns downstream are covered in more depth on our local pages for Yalding and Maidstone, and across the county on our Kent overview.

Is the River Teise a Main River — and what that means for your site

Through its middle and lower reaches, yes. The Environment Agency has designated the Teise a Main River, which means the Agency, rather than the local council, is the regulator for the channel and its immediate margins. That distinction is not academic if you are developing nearby. Works within 8 metres of the top of the bank generally need a Flood Risk Activity Permit from the Environment Agency before they start, and a site in the river’s floodplain will normally need a flood risk assessment to support a planning application. The many small brooks, field ditches and headwater streams that feed the Teise are ordinary watercourses instead, regulated by the Lead Local Flood Authority and by the riparian owners whose land they cross. Work affecting one of those usually needs ordinary watercourse consent from the council instead — and getting the classification right at the outset saves time later.

• The 8 metre byelaw margin. Building, excavation or structures near the Teise usually require a Flood Risk Activity Permit, sought alongside — not instead of — planning permission.
• Flood zones drive the assessment. A site in Flood Zone 2 or 3, or a larger site in Flood Zone 1, needs a flood risk assessment for planning.
• Know which watercourse you are on. The main river is Environment Agency territory; its tributaries are ordinary watercourses under the Lead Local Flood Authority. We confirm this for every site.

Flood risk and drainage services for sites near the River Teise

A development near the Teise can call for several different reports, and it helps to be clear that they answer different questions. A flood risk assessment, a sequential or exception test and a drainage strategy are three distinct reports. They often travel together in a planning submission, but they address separate things: whether the site is safe from flooding, whether the development should be located here, and where the surface water goes. Unda prepares each of them for sites across the River Teise catchment.

• Flood risk assessments for planning. Site-specific assessments dealing directly with the Environment Agency’s requirements for development in the river’s flood zones. See our flood risk assessment for planning service.
• Assessments for property purchase and insurance. Independent reports for buyers, owners and lenders through our flood risk survey for property purchase and flood risk assessment for insurance.
• Drainage strategies and SuDS. Surface-water designs that manage runoff on heavy clay and meet the discharge limits set by the Lead Local Flood Authority — see our sustainable drainage strategy service and the four pillars of SuDS.
• Sequential and exception tests. Locational justification where policy requires it, through our sequential and exception test reports.
• BREEAM and groundwater. A BREEAM flood risk assessment for the Pol 03 credit, and a groundwater flood risk assessment where a high winter water table on the clay is in play.

Where national mapping is not enough — a common situation for sites right beside a Main River — we can bring in hydraulic flood modelling to derive accurate flood levels and extents, prepare the preliminary drainage design a scheme needs, and produce the detail required to discharge a drainage condition. A topographical survey is often the piece that makes a riverside assessment robust. Everything we do is framed by the NPPF and its planning practice guidance.

Managing flood risk on the River Teise: policy and contacts

Several bodies share responsibility for flood risk on the Teise, and it is worth knowing who does what. The river sits within the Medway management catchment, part of the South East river basin district. The Environment Agency regulates the Main River, publishes the flood map for planning and issues flood warnings; Kent County Council is the Lead Local Flood Authority for surface water, groundwater and ordinary watercourses across most of the catchment, with East Sussex County Council covering the headwaters around Wadhurst; and Tunbridge Wells, Maidstone and Tonbridge & Malling are the planning authorities that decide applications along the river, each with its own strategic flood risk assessment. Downstream, the Leigh flood storage area and the Middle Medway scheme manage the flows the Teise feeds into around Yalding.

• Live river levels. Check the river’s gauges on the Environment Agency service — River Teise at Stonebridge and River Teise at Lamberhurst — or use our own live river levels map.
• Screen a location. Try our free flood risk map and, for drainage on clay, the drainage calculators, the BRE 365 infiltration calculator and our ground conditions and soakaway map.
• Flood warnings. Sign up for Environment Agency flood warnings and call Floodline on 0345 988 1188.
• In a flood emergency. Call 999 if life is in danger, and 105 for power cuts.

The wider picture for the river — its catchment, water bodies and status — is published on the Environment Agency’s Medway management catchment pages.

How Unda helps with flood risk on the River Teise

Unda understand how a clay-catchment river like the Teise behaves in flood, and what the planning system and the Environment Agency expect from the reports that follow. We know how quickly this river responds to rain, where its floodplain bites hardest through Lamberhurst, Marden and the approach to Yalding, and what a robust, compliance-led flood risk assessment has to demonstrate to carry a development through planning. We prepare assessments and drainage strategies for developers, planning consultants, architects, agents and homeowners with sites the length of the valley and its two lower arms.

Every assessment rests on the same evidence the regulators use: the Environment Agency’s flood mapping, the river’s gauged levels and modelled flows, and the local planning policy that applies to the site. If you are working on a site near the River Teise, talk to one of our experienced flood risk consultants about what your application will need.

River Teise flood risk: your questions answered