Environmental Engineering Reference
In-Depth Information
The old water mills are now derelict and only in a very few cases are the mill-wheels intact. The
floodgates no longer pen the waters, which hitherto loitered in the pounds and gurgled through the
penstrocks. The streams once again murmur unleashed along their ancient waterways.
Horatio Tucker,
Gower Gleanings
G
OWER IS A DISTINCT
hydrological region, separate from the rest of Glamorgan. In particular, rainfall
over most of the peninsula is much less and the hydrology is much more lowland in character than in the
rest of the county. Open freshwater areas are scarce in South Wales and consequently much of the wildlife
associated with freshwater marshes, ponds, streams and rivers is of particular interest to the naturalist.
There are no large rivers in Gower, although there are numerous streams such as the Morlais, known
as the Morlais River, and the Burry Pill, which drain into the inlet and estuary, while others such as the
Bishopston Stream and Pennard Pill drain directly into the sea. Together the Morlais River and the Clyne
River to the south form a convenient boundary to the peninsula. Most of the lower sections of the water-
courses are known as 'pills'; the English word
pill
has been interpreted as a loan from the Welsh
pyl
, 'a
tidal creek, a pool in a river'. The word 'lake' is also sometimes used, in this case meaning stream, as at
Moor Lake near Lagadranta and Diles Lake at Hillend. The particular names of these pills can also be in-
teresting. Caswell, for example, is derived from
carswell
, meaning 'cress stream', and water-cress
Rorippa
nasturtium-aquaticum
can still be found along its course.
Other freshwater habitats include pools, ponds and springs. Of the numerous pools that occur on the
commons the largest and best known is Broad Pool on Cefn Bryn Common. There are also a large num-
ber of farm ponds, mainly in the west of the peninsula. For geographical reasons freshwater marshes are
relatively uncommon in the west of Britain and large unpolluted, undisturbed examples such as Oxwich
are rarer still. The marsh is therefore one of the most interesting and valuable freshwater habitats in the
peninsula, especially as the reedswamp it contains, which covers about 40 hectares, is one of the largest in
Britain.
THE DRAINAGE PATTERN
The dominant influence in terms of the drainage pattern is the limestone that outcrops to the north and
southofthecentral ridgeofCefnBryn.Theresultisthatthereissubsurfacedrainage overquitelargeareas
(Fig. 125). The flow regimes of the small streams, many of which arise from the sixty or so springs which
exist, are very even, low flows, maintained by an extensive groundwater store in many areas. Depressions
intheground,disappearingstreams,undergrounddrainage,dryvalleysandothersimilarcharacteristicsare
typical of limestone areas such as Gower. Such terrain is generally known by the German term
karst.
Karst
landscapes are primarily the result of limestone being selectively chemically dissolved by acidic natural
