Chapter XIX: Appendix: B

=Pitching and Bed Protection= (CHAP. VI., _Art. 3_, and CHAP. X., _Art. 2_).--Any scour upstream of a weir is merely due to the eddies formed upstream of the crest (_Hydraulics_, CHAP. II., _Art. 7_), and is not serious. And, similarly, as to scour upstream of a pier. A hole formed alongside a pier or obstruction, if there is no floor, may work upstream. The chief use of a floor extending far upstream is to flatten the hydraulic gradient (CHAP. X., _Art. 3_).

For pitching of the sides, monolithic concrete is not very suitable, because it may settle unequally and crack. For heavy pitching, concrete blocks can be used. They can rest on a layer of 3 to 6 inches of rammed ballast or gravel. The toe wall, as shown in fig. 13, page 65, is sometimes dispensed with, the pitching being merely continued to a suitable depth below the bed, and the bottom edge being at right angles to the slope instead of horizontal. The portion below the bed may be of concrete.

INDEX

Abrupt changes in streams, 28.

Alterations in a channel, upstream effect, 4.

Aqueduct, Kali Nadi, 149.

Available rainfall, 9.

Bank protection, 60.

-- -- artificial weeds, 70.

-- -- berms, 70.

-- -- bushing, 68.

-- -- fascining, 66.

-- -- heavy stone pitching with apron, 71.

-- -- on the Adige, 67.

-- -- reinforced concrete, 70.

-- -- rolls of wire-netting, 70, 140.

-- -- staking, 69.

-- -- trees, 68.

-- -- twig revetment, 68.

-- -- Villa system, 69.

Banks, 92.

-- Bell’s guide, 137.

-- continuous lining of, 64.

-- dimensions of, 93.

-- guide, 137.

-- side slopes of, 92.

Barrage of the Nile, Assiut, 117.

Bars, river, 203.

Bed, protection of, 58.

-- -- Villa system, 59.

Bell’s guide banks, 137.

Bends, effect of, 44.

-- short cuts of, 44.

Bengal Dooars Railway, bridge and floods, 139.

Bifurcation of a channel, 53.

Birmingham water supply, 173.

Borrow-pits in bed of channel, 53.

Breakwaters, converging, 207.

Bridges, 132.

-- foundations or floor, 132.

-- on Indian rivers, 134.

-- piers and abutments, 132.

-- protection of, 137.

-- at Wazirabad, 134.

British Rainfall Organisation, 9.

Canalisation of rivers, 84.

Canals, 92.

-- fall, 113.

-- headworks, 54.

-- navigation, 93.

-- rapid, 113.

-- Ship, 95.

Catchment area, “yield,” 9.

Channel, alterations in, 4.

Chanoine falling shutters, 121.

Chenab River at Shershah, 210.

Choice of types of work, 3.

Closures of streams, Colorado River, 80.

-- -- cradle for, 78.

-- -- Tista River, 81.

Collection of information concerning streams, 18.

Colorado River, closure of, 80.

Conduits, 92, 100.

Cradle for closing streams, 78.

Culverts, 135.

-- flooding of, 136.

Dams, culvert of, 180.

-- design of masonry, 181.

-- earthen, 174.

-- masonry 181.

-- -- construction of, 185.

-- -- design, 181.

-- -- failures of, 185.

-- -- stresses in, 185.

-- pitching of, 179.

-- reservoir, 162.

-- Sidhnai Canal, 117.

-- tower for culvert, 180.

Dee estuary, 201.

Dera Ghazi Khan, Indus at, 71.

Discharge curves, 23.

-- observations, 21.

-- tables, 24.

Divide wall, Gagera branch canal, 209.

Drainage, 141.

Dredging and excavating, 84, 88.

Drift, littoral, 205.

Eddies, scouring power of, 28.

Embankments, 156.

-- design of, 157.

-- Holland, 159.

-- Irrawaddy, 159.

-- Rhine, 159.

-- slips in, 177.

Estuaries, Dee, 201.

-- Mersey, 202.

-- Seine, 200.

-- tidal, 197.

Fall, canal, 113.

Fallacies in hydraulics, 5.

Falling shutters, Chanoine, 121.

-- -- Fouracres, 121.

-- -- Khanki, 124.

-- -- Thénard’s, 121.

Flood discharge, estimating, 148.

Floods, 141, 146.

-- Bengal Dooars Railway, 139.

-- formulæ for, 147.

-- prediction, 150.

-- prevention, 153.

Flowing stream, closure of, 75.

Ford in a river, 43.

Forests and vegetation, influence of, on rainfall, 14.

Formulæ for floods, 147.

Groynes or spurs, 58, 60, 61.

-- on the Indus, 53.

Guide banks, 137.

Headworks of a canal, 54.

Holland, embankments, 159.

Hurdle dykes, 79.

Hydraulics of open streams, 4.

-- -- fallacies in, 209.

Important works, precautions at, 130.

Indian rivers and bridges, 134.

Indus, groynes on, 53.

Information concerning streams, collection of, 18.

Inundation canal, flume in, 209.

Irrawaddy, embankments, 159.

Irrigation channels in embankment, 52.

Irwell, weir on, 124.

Jetties, in continuation of river banks, 204.

-- Mississippi, 205.

-- Richmond River, New South Wales, 206.

Kali Nadi, aqueduct, 149.

Khanki, falling shutters at, 124.

Leakage, stoppage of, 78.

Lockage, 98.

Locks, 96.

-- in flights, 98.

Mersey estuary, 202.

Mississippi jetties, 48.

Narora weir, 109.

Navigation canals, 93.

Needles, regulator, 117.

New South Wales, available rainfall, 12.

Obstruction, effect of, 5.

Obstructions in streams, 28.

Okla weir, 112.

Open streams, hydraulics of, 4.

Perishable materials, use of, 4.

Permanent régime of streams, 29.

Pitching, 64.

Prediction of floods, 150.

Prevention of floods, 153.

Protection of banks (see Bank protection).

Rainfall, 6.

-- available, 9, 26.

-- -- New South Wales, 9.

-- -- Sudbury River, Massachusetts, 12.

-- -- various countries, 11.

-- British Organisation, 9.

-- “catchment area,” “basin,” 9.

-- distribution of, 7.

-- driest year, 7.

-- evaporation, 9.

-- heavy falls in short periods, 15.

-- influence of cultivation, 15.

-- -- of forests and vegetation, 14.

-- local figures, 8.

-- measurement of, 13.

-- observations, period of, 7.

-- statistics, 6.

-- variation of, 6.

Rain-gauge, 8, 13.

Rapid, canal, 113.

Regulators, 118.

Reservoirs, 162.

-- capacity, 167.

-- compensation water, 162.

-- leakage, 163.

-- waste weir, 164.

Résumé of the subject, 1.

Rhine, embankments, 159.

Richmond river, jetties, 206.

-- weir at, 119.

River bars, 203.

-- training groynes, 85.

-- -- walls, 85.

Rivers, deltaic, 203.

-- floods in, 146.

-- non-deltaic, 205.

-- tidal, 192.

-- training and canalisation, 84, 89.

Run-off in small streams, 143.

Salt water, effect of, 29.

Sand separator, 34.

Sandbanks, 47.

Scour (see Silt and scour).

Seine estuary, 200.

Set of stream, effect of, 5.

Ship canals, 95.

Shutters, self-acting, Switzerland and Bavaria, 127.

Silting and scouring, 27.

Silt and scour, action at bends, 42.

-- -- -- on sides of channel, 40.

-- -- effect of regulator or movable weir, 49.

-- -- in the Sirhind Canal, 32, 54.

-- -- increasing or reducing, 48.

-- -- materials carried in suspension, 3.

-- -- methods of investigation, 33.

-- -- practical formulæ and figures, 37.

-- -- production of, 48.

-- -- rolled materials, 29.

-- -- sand separator, 34.

-- -- scrapers or harrows, 48.

-- clay and sand, 36.

-- deposit, production of, 51.

-- in river Sutlej, 35.

-- in river Tay, 35.

-- quantity and distribution of, 35.

-- upstream of weirs, 103.

Sidhnai Canal, dam, 117.

Sirhind Canal, silt and scour in, 32, 54.

Slips in embankments, 177.

Sluice gates, Stoney’s, 119.

Sluices, 102.

Small streams, floods in, 141.

Soundings, 21.

Spurs or groynes, 58, 60, 61.

Stream gauges, 19.

-- diversions of, 73.

-- general tendencies of, 45.

-- information concerning intermittent, 25.

-- -- -- small, 24, 25.

-- overflow, 46.

-- shifting, 20, 47.

Sudbury River, Massachusetts, available rainfall, 12.

Surface slope observations, 22.

Survey of a stream, 21.

Sutlej River, silt in, 35.

Syphons, 132, 135.

Tay River, silt in, 35.

Teddington, weir at, 119.

Tidal estuaries, works in, 198.

-- river, diagrammatic route-guide, 196.

-- rivers, 192.

-- works in, 196.

Tide-gauges, 192.

Tides, 190.

Tista River, closure of, 81.

Training of rivers, 84.

Types of work, choice of, 3.

Upper Jhelum Canal, syphons to carry torrents, 144.

Velocities which enable a stream to scour, 40.

Villa system of bank protection, 69.

-- -- bed protection, 59.

Waste weir, hydraulic problem, 165.

Water supply, Birmingham, 173.

Waterway, area of, in regulators, 129.

Wave, travel of, down a stream, 152.

Waves, effect of, 29.

Wazirabad, bridge at, 134.

Weeds, artificial, 70.

-- growth of, 29.

Weirs, 102.

-- adjustable, 126.

-- Bear Trap, 123.

-- drum, 127.

-- frame, 120.

-- general design of, 105.

-- Narora, 109.

-- oblique, 103.

-- Okla, 112.

-- on sandy or porous soil, 106.

-- Richmond, 119.

-- silt deposit, upstream of, 103.

-- types of, 111.

-- waste, 164.

-- with sluices, 115.

Wire-netting for bank protection, 70, 140.

Works, design and execution of, 3.

Zifta Regulator, 109.

PRINTED BY NEILL AND CO., LTD., EDINBURGH.

FOOTNOTES:

[1] _Min. Proc. Inst. C.E._

[2] _Engineering News._

[3] _Encyclopædia Britannica._

[4] The paper by Spring--in size it is a book--will repay perusal by engineers engaged on railway bridges over large shifting rivers. London Agents, Constable & Co.

[5] _Hydraulics with Working Tables._ Spon, 1912.

[6] Irrigation canals are dealt with in _Irrigation Works_ (Spon, 1913).

[7] See also Appendix A.

[8] The regulator runs across the canal head; the under-sluices are a continuation of the weir, between the divide wall and the regulator.

[9] See also Appendix B.

[10] On Indian canals the term “regulation” is applied to the control of the discharge at the regulators or off-take works.

[11] See also Appendix B.

[12] _Irrigation Works_, CHAP. I., _Art. 4_.

[13] _Min. Proc. Inst. C.E._, vols. lx. and lxxxv.

[14] _Rivers and Canals_, Harcourt.

[15] _Rivers and Canals_, Harcourt.

[16] _Rivers and Canals_, Harcourt.

[17] The foundations of piers and abutments should be deep enough to allow of this.

[18] _Report on the Revised Estimate, Upper Jhelum Canal._

[19] _Revised Estimate of the Upper Jhelum, Upper Chenab, and Lower Bari Doab Canals._

[20] See also Note on p. 161.

[21] The height of a wave is supposed to be 1·4√(fetch), but this allows nothing for splashing.

[Transcriber’s Note:

Obvious printer errors corrected silently.

Inconsistent spelling and hyphenation are as in the original.]