Small Decentralized Hydropower Program National ... - Cd3wd.com
Small Decentralized Hydropower Program National ... - Cd3wd.com
Small Decentralized Hydropower Program National ... - Cd3wd.com
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Los Desripkdores consisten en un profundi-<br />
zaci6n de la Solera de1 canal de aproximada-<br />
mente 50 cm. x 50 cm. con 1un talud de entrada<br />
de 1:l a 1:2 y una <strong>com</strong>puerta de purga (ver<br />
esquema Bocatoma cork. A-A).<br />
Los Desarenadores e&n indkados en 10s<br />
disefios tipicos que se refieren a Desarenadores<br />
<strong>com</strong>pletes.<br />
Se debe tener en cuenta qw, para una buena<br />
decantaci6n de material de 0.3 mm., la<br />
velocidad de1 agua no debe ser mayor de 20<br />
cm/s.<br />
T $0~ Desarenadores Preliminares 6 Auxiliares<br />
pueden ser de tamar?o menor, se@n las<br />
posibilidades de1 terreno hasta para decantar<br />
&Jo material de 0.75 mm., sin embargo, la<br />
velocidad de1 Gagua no debe ser superior a 10s 35<br />
cm/s.<br />
Cuando ei terreno es plan0 y permite con-<br />
struir un Desarenador - ancho, sin mayor costo,<br />
conviene siempre construir un Desarenador<br />
m&s an&o y corto disminuyendo asi la velocidad<br />
de1 aqua.<br />
En la tabla siguiente se indican las medidas<br />
principales de Desarenadores, <strong>com</strong>pletes y<br />
preliminares para diferentes condiciones de<br />
terreno.<br />
9. Para eliminar la erosi6n profunda al pie de1<br />
Barraje (aguas abajo), y cuando no se puede<br />
llevar 10s cimientos de1 Barraje a terreno firme<br />
e impermeable es muchas veces conveniente<br />
construir una Cont~asolera a poca distancia de1<br />
Barraje, creando asi un Colch6n de Agua entre<br />
Barraje y Contrasolera de unos 30-80 cm. de<br />
profundidad. El fondo de este Colch6r de Agua<br />
- puede quedar sin revestimientos, si contiene<br />
pledras grandes - que resisten la erosi6n y si no<br />
hay filtraciones muy fuertes debajo de la<br />
Contrasolera.<br />
Cenales de Conduccih<br />
Se indican diferentes secciones de canales<br />
revestidos con concrete, con pendiente de 1%. Es<br />
conveniente considerar tambien otros tipos de secci6n,<br />
revestidos 6 sin revestir, y con diferentes pendientes.<br />
Se agrega al plano un perfil hidraulicamenk<br />
mas favorable, con inclinacidn de las paredes de 2:l.<br />
Aumentando la pendiente de1 canal de 1% a 2.5% se<br />
aumenta la capacidad de1 canal en un 60%, pudien-<br />
canal<br />
Depending on the local conditions, in the<br />
river as well as in the area of the canal and<br />
the turbine, the removal of sand should be<br />
done at the intake and the forebay in one<br />
of the following <strong>com</strong>binations:<br />
1. Preliminary removal of sand or larger<br />
debris at intake and <strong>com</strong>plete removal at<br />
the foreLay.<br />
2. Complete removal of sand at intake and<br />
a back-up removal at the forebay.<br />
The sand trap for preliminary removal of<br />
sand and debris consists of a deepening of<br />
the intake area to approximately 50 cm. x<br />
50 cm. just in front of the trash rack, with<br />
an upstream slope of 1:l to I:2 and a gate<br />
to permit flushing of the sand trap (See In-<br />
take drawing, A-A view). We have to keep in<br />
mind that, for good sedimentation of<br />
material of 0.3 mm, the speed of the water<br />
should not be higher than 20 cm/s. The<br />
prelir,linary or auxilliary sand traps may be<br />
smaller in size, depending on the suitability<br />
of the terrain for sedimentation of material<br />
up to 0.75 mm. However, the speed of the<br />
water should not be above 35 cm/s.<br />
When the terrain is flat and permits the<br />
construction of a wide sand trap without<br />
major cost, it is always convenient to build<br />
a wider and shorter sand trap to decreasing<br />
the speed of the water. The following table<br />
shows the measurements of the sand<br />
traps, for both preliminary and <strong>com</strong>plete<br />
sand removal, to suit different site condi-<br />
9. To prevent deep erosion at the foot of the<br />
dam (down stream) and when its founda-<br />
tion cannot be carried to firm and im-<br />
permeable terrain, it is frequently conve-<br />
nient to construct a low wall a short<br />
distance downstream from the dam, suffi-<br />
cient to create a waterbed between the<br />
dam and this wall of 30 to 80 cm in depth.<br />
The bottom of this waterbed may be left<br />
without lining, if it contains big rocks to<br />
protect against erosion and if there is no<br />
strong seepage under the low wall.<br />
dose asi en muchos cases, disminuir la secci6n de1 Different rectangular and trapezoidal canal<br />
canal y reducir 10s costos. En otros cases, especial- sections lined with concrete, with a slope of one<br />
mente en terreno rocos, puede convenir dejar el per thousand, are shown below. Other sections<br />
149<br />
tions.