this normally placid river looks harmless most of the time, it can
become dangerous during times of heavy rain or storms. If you see the
water level high and the current strong keep well clear. The
river has been the source of some flooding through the years. This has
been exacerbated by dense built development along its course covering
what were at one time natural flood plains.
The Ravensbourne rises at Caesar's Well at Keston Ponds but we are told that much of that source of water is taken by Thames Water before it reaches Beckenham Place Park. Other tributaries in the Bromley Common/Orpington area feed the Ravensbourne that runs through the park and on to Catford and Lewisham and into the Thames at Deptford Creek.
Again, some of these tributaries are slow running or dry most of the time but can be subject to flash flooding in extreme conditions.
On its way to the Thames other tributaries join it, the Pool joins just before Catford Bridge and the Quaggy joins it near Lewisham Station. The Pool river itself has collected water from the Beck (or Hawksbrook), the Boundary Stream and the Chaffinch brook. These join at Cator Park after flowing via Kelsey Park (the Beck) and South Norwood Country Park (the Chaffinch).
Several stretches of the River are conduited under urban development or in concrete channels. There are some areas which approach a natural watercourse in appearance and some works have been done to return the river to a more environmentally friendly habitat in areas along the Quaggy, Pool and Ravensbourne. Water quality varies as the rivers on this system acquire road run-off from rainfall and some pollution from industry and domestic sites along its course. Shopping trolleys and other litter make their way to Deptford Creek where it has been found they make a good breeding environment for fish! Flood control practices have changed over the years from conduiting and concrete channels to allowing the rivers to return to natural riverbeds. The Environment Agency has removed tow boards along the river in the park and were planning to remove concrete channeling further up river in Glassmill Lane, Bromley but this work seems to have been cancelled. The Quaggy has had extensive works in the Kidbrooke park area and The Ravensbourne has had new channels excavated through Ladywell Fields. There have in the past been serious floods in Beckenham and Lewisham from the Ravensbourne and its tributaries. However, this has to be considered the result of building on flood plains, a practice which is still pursued even though it is known that periodic flooding will occur.
Kingfishers are regularly seen in Beckenham Place Park and other stretches of the river. The lake in Kelsey Park has an island which has become a Heronry over the last 20 years or so. Little Egrets are now a regular visitor to the river and ponds along it as well as also nesting in Kelsey Park. Snipe have been seen in harsh winters. Ducks, Coots and wagtails are regularly seen.
These rivers were once the source of energy for light industry having flour mills and cutlery factories along their route. There were also several artificial lakes such as still exists in Kelsey Park. The ornamental lake in Beckenham Place which dried up during the 20th Century through a combination of poor imperviousness of the clay lining, lack of maintenance and drying up or diversion of the water source which was via the now 'extinct' Foxgrove moated farm. Maps from the 19th century show a watercourse from Kelsey park via Foxgrove Farm to the lake in BPP and thence, to the Ravensbourne. This would have been cut off by the building of the railway we assume.
The new lake in Beckenham Place is filled by groundwater from rainfall in the park and by water from a borehole. It is unlikely that much water from the lake will make its way to the Ravensbourne but a drain from the old lake used to run under the railway and the area known as the Common to the Ravensbourne for any overflow. What would happen in extreme weather conditions hasn't so far been observed (2021).