98 SCIENTIFIC SURVEY OF BLACKPOOL AND DISTRICT 



well, and the back wash from a section of this description is reduced to a 

 minimum. 



Two slades were provided for in the scheme, each 100 yards in length, 

 7 yards in width, with an inclination of 1 in 14 : also eight flights of P.C. 

 concrete steps, leading from the top of the wall to the foreshore, each 12 feet 

 in width. 



A good many groynes were erected from the old borough boundary to the 

 northerly boundary of the borough, for a distance of 4,900 yards. Four of 

 the first to be built were constructed in pre-cast concrete blocks, stepped in 

 section on both sides so as to minimise obstruction to pedestrians using the 

 foreshore. 



In plan they are part of an ellipse, with the sharp part of the curve com- 

 mencing at a tangent from the wall and leading away in a south-westerly 

 direction. The height of these groynes abutting the sea-wall is 1 6 feet above 

 O.D., and they continue at this level for a length of 48 feet, when they are 

 ramped down 1 foot in every 1 2 for a length of 1 80 feet. This type of groyne 

 has been very successful on this section of the foreshore. 



All the remaining groynes were built of timber, laced horizontally between 

 steel tram rails as piles driven at 6 feet centres, the timbers being laid in slots 

 formed in the rails and secured by iron clamps at the top. This method of 

 construction is cheap, and has served its purpose admirably, many of the 

 groynes having had to be lifted to prevent gravel travelling in a northerly 

 direction. 



The groynes are generally spaced 200 yards apart, and are approximately 

 80 to 100 yards in length. 



This section of the sea-coast protection works, a length of 1 ,980 yards, was 

 completed in 1921 at a cost of approximately £80,000, including the seaward 

 wall built opposite Uncle Tom's Cabin to enclose the proposed open-air bath 

 site at the then northerly end of the borough. This site at the present time 

 is let as a boating pool. 



Attrition, due to gravel and boulders driven during the heavy seas against 

 the self-faced wall, is, generally speaking, not so bad. As far as possible, 

 the shuttering on the seaward side of the wall was struck, having due regard 

 to the weather conditions and the height of the tides, during low tides and 

 favourable weather. The lower profiles and shutters were struck after four or 

 five days : the top profiles stood eight to 10 days before striking, and during 

 high tides, coupled with unfavourable weather, the front shuttering was left 

 until more favourable weather prevailed. 



In connection with this work a scheme was inaugurated to preserve the 

 natural amenities of the cliffs. The face of the cliff from the base is retained 

 in position by artificial rockery, and above, where the slope makes its natural 

 inclination, grasses were planted, and after a number of experiments with 

 various kinds, a degree of success has been obtained. 



From the top of the cliffs to the Lower Walk, footpaths have been constructed 

 in a pleasing and artistic manner, natural stone rubble walling being built 

 where necessary, and inclined pathways formed with crazy paving. 



