He is alleged to have completed the system of nine canals and weirs in three years' time.
Provided for the removal' of kydells, or weirs, from all English rivers.
From Tewkesbury; the locks from Evesham upward to Stratford (17 m.) are decayed, but the weirs, and mill-dams still higher, afford many navigable reaches to pleasure boats.
The number of locks is 47, including four navigation weirs above Oxford.
Francis (Lowell Hydraulic Experiments, Boston, Mass., 1855) led him to propose variations in the accepted formulae for the discharge over weirs, and a generation later a very complete investigation of this subject was carried out by H.
The products of the textile industry in America were bark cloth, wattling for walls, fences and weirs, paper, basketry, matting, loom products, needle or point work, net-work, lacework and embroidery.
Rough weirs, formed of stakes and twigs, were erected across English rivers in Saxon times for holding up the water and catching fish, and fish-traps, with iron-wire meshes and eel baskets, are still used sometimes at weirs.
Weirs are essential for raising the head of water for water-wheels at mills, and for diverting some of the flow of a river into irrigation canals; but they have received their greatest and most varied extension in the canalization of rivers for navigation.
There are three distinct classes of weirs, namely, solid weirs, draw-door weirs, including regulating sluices for irrigation, and movable weirs, which retain the water above them for navigation during the low stage of the river, and can be lowered or removed so as to leave the channel quite open in flood-time.
These weirs, if solidly constructed, possess the advantages of simplicity, strength and durability, and require no superintendence.
This serious defect of solid weirs, where the riparian lands are liable to be injured by inundations, can be slightly mitigated by keeping down the crest of the weir somewhat below the required level, and then raising the water-level at the low stage of the river by placing a row of planks along the top of the weir.
Waste weirs resemble ordinary solid weirs in providing for the surplus discharge from a reservoir of an impounded river or mountain stream over their crest; but in reality they form part of a masonry reservoir dam for storing up water for water-supply or irrigation, kept purposely lower than the rest of the dam to allow the excess of water to escape down the valley (see Water-Supply).
This arrangement has been provided at several weirs on the Thames, to afford control of the flood discharge, and reduce the extent of the inundations; the largest of these composite weirs on that river is at the tidal limit at Teddington, where the two central bays, with a total length of 2421 ft., are closed by thirty-five draw-doors sliding between iron frames supporting a foot-bridge, from which the doors are raised by a winch.'
The barrage at the head of the Nile delta, and the regulating sluices across the Nile at Assiut and Esna in Upper Egypt below Assuan, are examples of draw-door weirs, with their numerous openings closed by sluice-gates sliding on free rollers, which control the discharge of water from the river for irrigation.
- There are three main types of movable weirs, namely frame weirs, shutter weirs and drum weirs, which, however, present several variations in their arrangements.
The addition of a foot-bridge greatly facilitates the raising and lowering of these shutter weirs, and also aids the regulation of the discharge; but it renders this form of weir much more costly than the ordinary frame weir, and where large quantities of drift come down with sudden floods, the frames of the bridge are liable to be carried away, and therefore boats must be relied on for working the weir.
The drum weirs erected across shallow, regulating passes on the river Marne in1857-1867comprise a series of upper and under wrought-iron paddles, which can make a quarter of a revolution round a central axis laid along the sill of the weir.
Accordingly, for several years its use was restricted to the Marne; but in1883-1886drum weirs were 2 Proc. Inst.
Adopted for closing the timber passes alongside the needle weirs placed across the Main, with a single upper paddle 393 ft.
When a river partakes of the nature of a torrent, dwindling to a paltry stream at one season and swelling into an enormous flood at another, it is impossible to construct a system of irrigation canals without very costly engineering works, sluices, dams, waste-weirs, &c., so as to give the engineer entire control of the water.
Across the apex of the deltas are built great weirs (that of the Godaveri being 22 m.
But this was looked on as too near the limit of safety to be relied on, and in 1899 subsidiary weirs were started across both branches of the river a short distance below the two barrages.
These weirs were satisfactorily completed in 1901.
The Sangam and Pennar systems depend on two weirs on the river Pennar in the Nellore district, the former about 18 m.
The system consists of weirs over the rivers Gulleri, Mahanadi and Rushikulya in the backward province of Ganjam, south of Orissa.
From these weirs flow canals altogether about 127 m.
From its centre, are the grounds of the Winnepesaukee Camp-Meeting Association, and the camping place for the annual reunions of the New Hampshire Veterans of the Civil War, both at The Weirs, the northernmost point in the territory claimed by colonial Massachusetts; about 2 m.
From the centre of Laconia is Lakeport (pop. 1900, 2137), which, like The Weirs, is a summer resort and a ward in the city of Laconia.
Weirs in the streams), water-mills, saltpans (if by the sea) and other subsidiary sources of revenue; the peasants are enumerated in their several classes; and finally the annual value of the whole, past and present, is roughly estimated.
Some of the clauses are unimportant concessions to individuals, or deal with matters of trifling importancesuch as the celebrated weirs or kiddies on Thames and Medway, or the expulsion of the condottieri chiefs Gerard dAthies and Engeihart de Cigogn.