Water Supply. 273 



Deio-Ponds. 



These ponds are chiefly constructed on the highest ridges of 

 the chalk range, whether in down or under arable cultivation, 

 for the purpose of supplying water to the sheep stock during the 

 summer months. In a known instance, the increase of these 

 ponds on an extensive farm, high on the chalk range, has been 

 made the subject of arrangement between a landlord and an 

 incoming tenant, with a view to the introduction of steam-culti- 

 vation. Though careful and wide-spread inquiry, with repeated 

 personal observation, have failed to clear up the difficulties pre- 

 sented by the sustained supply of water in these ponds, notwith- 

 standing the drain on them by the daily demands of sheep and 

 other stock, the following facts may be relied on, and will tend 

 to show their great value to the flockmasters of a district where 

 many breeding flocks are sustained during the summer months, 

 when a good supply of water is essential to their well-being. 

 Natural springs, as supplies, are out of the question on the 

 summit of the chalk range, since the chalk water-level lies from 

 100 to 400 feet beneath these ponds. 



The site selected is generally at the highest elevation on the 

 ridges or spurs of the chalk hills, where they can receive no run 

 of surface-water, though instances may be found where they are 

 placed near roads on hill-sides, and so receive the run after heavy 

 rains ; of the former alone here it is proposed to speak, as they 

 present phenomena not easily accounted for by recognised phy- 

 sical causes. 



These ponds are constructed by persons of experience and 

 skill. At the spot selected an excavation is made in the sur- 

 face of the chalk, either round or rectangular, from 30 to 40 feet 

 or more in diameter, from 4 to 6 feet deep. The bottom, of a 

 basin shape, is covered in portions with clay carefully tempered, 

 mixed with a considerably quantity of lime to prevent the work- 

 ing of the earth worms. As the portions are finished they are 

 protected from the action of the sun and atmosphere by a covering 

 of straw ; when the Avhole bottom of the pond is so covered with 

 an efficient and impermeable coating or puddle, a layer of broken 

 chalk is placed upon it to prevent its injury by cattle or other 

 means. Their cost varies from 30/. to 50/. When all is finished, 

 water is introduced by artificial means. If there is a fall of snow, 

 this is collected and piled up in the pond, as the readiest and 

 least expensive method of accomplishing the object. During the 

 falling of the snow in January, 1865, with a strong wind blowing, 

 flaked or wattled hurdles we're so placed that the drifting snow 

 accumulating against them readily filled a pond on one of the 

 highest ridges of the chalk range of hills, Ponds so constructed 



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