Regarding the use of spurs or groynes for diversion works or for reducing the width of a stream, see CHAP. VII., _Art. 1_, and CHAP. VIII., _Art. 3_. 2. =Spurs.=--A spur may be made of-- (_a_) Loose stone, which may be faced with rubble above low-water level (fig. 7). (_b_) Layers of fascines weighted with gravel or stones. (_c_) Earth or sand closely covered with fascines. (_d_) A double line of stakes with fascines or brushwood laid between them (fig. 8). (_e_) A single line of stakes with planking or basket work on its upstream side, or with twigs or wattle laid horizontally and passed in and out of the stakes, as in fig. 20. (_f_) A single tree with the thick end of the trunk on the bank and with stakes, if necessary, to prevent the current from moving it. (_g_) A number of small trees heaped together and weighted with nets full of stones. (_h_) A layer of poles and over them a layer of fascines on which are built walls of fascine work so arranged as to form cells or hollow rectangular spaces which become filled with silt. (_i_) Large fascines running out into the stream and having their inner ends staked to the bank while the outer ends float, other fascines being added over them and projecting further into the stream, and the whole eventually sinking. [Illustration: FIG. 8.] Combinations of the above are also used, for instance, (_d_) or (_e_) may be used for the upper portion, the foundation being (_a_) or (_c_). [Illustration: FIG. 9.] [Illustration: FIG. 10.] [Illustration: FIG. 11.] Instead of running out at right angles to the bank a spur may be inclined somewhat downstream. This somewhat reduces the eddying and scour round the end. The ends of a system of spurs should be in the line which it is intended that the edge of the stream shall have (fig. 9). The tops of short spurs are usually above high flood level. Sometimes spurs are made to slope downwards (fig. 10), and they then cause less disturbance of the water and less scour than if built to the form shown by the dotted line. Such spurs are sometimes combined with a low wall running across the bed of the stream, the whole forming a “profile” of the cross-section to which it is intended to bring the channel. Regarding such walls, see CHAP. V., _Art. 6_. When a spur is long it may have small subsidiary spurs (fig. 11) to reduce the rush of water along it; or its end may have to be protected in the same manner as the advancing end of a closure dam (CHAP. VII., _Art. 2_).