GC: n
CT: The rear apron in the Merala weir is of as soUd construction as the fore apron and is built on a slope right up to crest level; this arrangement facilitates discharge. The velocity of approach must be very great to necessitate huge book blocks of concrete 6X6X3 feet being laid behind the slope and beyond that a 40-foot length of riprap. The fore apron extends for 93 feet beyond the crest, twice as long as would be necessary with a weir of type A under normal conditions. The distance L of the talus is 203 feet against 182 feet calculated from formula (35a). That of the lower weir at Khanki is 170 feet. This shows that the empirical formula gives a fair approximation.
S: https://archive.org/details/cu31924004065664, p. 173 (last access: 1 February 2015)
N: 1. fore (adj): mid-15c., “forward;” late 15c., “former, earlier;” early 16c., “situated at the front;” all senses apparently from fore- compounds, which frequently were written as two words in Middle English.
apron (n): Middle English, alteration (resulting from false division of a napron) of napron, from Middle French naperon, diminutive of nape cloth, modification of Latin mappa napkin. First Known Use: 15th century.
A shield (as of concrete or gravel) to protect against erosion (as of a waterway) by water.
2. A concrete adjunct for spillway dams whose function is to increase the length of the path of percolation in the foundations and also provide a basin where the energy of the overflowing water may be safely dissipated.
S: 1. OED – http://www.etymonline.com/index.php?allowed_in_frame=0&search=fore+apron&searchmode=none (last access: 1 February 2015); MW – http://www.merriam-webster.com/dictionary/apron (last access: 1 February 2015). 2. GDT.
SYN: 1. downstream apron, downstream floor, downstream spillway apron (US), downstream concrete apron, downstream apron of concrete, concrete downstream apron. 2. lock-apron, apron of lock.
S: 1. GDT. 2. TERMIUMPLUS.
