Small Decentralized Hydropower Program National ... - Cd3wd.com

tan pobres ?o-:-‘:; hidrofitas en comparacion con 10s
lagos natur \.I-A. La magnitud de1 efecto de1 acopio
en lao 11; jrie. +- i:epeildetia en gran park de la
amplitdt-i C’L~ dlf 9~ Suctuacidn.
Ei el p:n~~ , ;kye un aumento on la caida
estAtic& cir ’ ,cyv;)rio, las comunidades terrestres
serkn inunoada~. La extension de un reservorio
aguas arriha inundatian las comunidades riparias.
La ext,ensibn iateral de1 reservorio simplemente
resultaria en un desplazamiento para arriba de la
ecologia existente en las lineas de la costa.
Estructura para un Andisis
Ye puede establecer una serie de eslabones para
relacionar la causa y 10s impactos de 10s eventos
ambientales asociados COT\ desarrollos de pequefias
plant?< de hidroenergfa. Se pueden utilizar estos
eslabones para comprender 10s impactos de primer
orden (directoF) y 10s de orden m&s alto (indirectos).
La ventaja de este sistema es que las relaciones se
pueden comprender y explicar con m&s facilidad.
Para objectives analiticos, estos eslabones pueden
ser construidos en matrices, jerarquicas y diagramas
de “espaguetti” para menclonar solo algunas. Los
tirminos que con&an estzs relaciones ambientales
son la causa, 10s cambios de condiciones, el efecto y
el impacto.
Causa
Est,e tkrmino describe el evento que imp&a o
fuerza 10s impactos eventua!es. Para 10s impactos de
primer orden, la causa es siempre fisica. La causa
puede ser discrcta o un evento que ocurre una sola
vez, tal coma una falla en el dique; puede ser de
origen discontinue o periodico tal coma una inundacion,
o puede ser continua coma una descarga con
muchz fuerza que acarrea gases disueltos en las
aguas recibidas.
Cambios de Condiciones
Este evento describe la condition fisica que
usualmente cambia coma resultado de la causa. El
cambio de las condiciones puede resultar a consecuencia
de m&s de una causa; unit situation m&s
compleja. Esta condicidn puede ser de naturaleza inmedia*&
coma un cambio de temperatura, una que
se desarrolle durante un period0 de tiempo o quiza
sea un evento que solo ocurritia bajo circunstancias
especiales tales coma las caracterkticas de la
estacion de incidencia solar, precipitaciones o
temperatura.
Efecto
Este termino se refiere a las consecuencias de1
92
hydropower is the small size - less tha 1 MW in
capacity - of the facility relative to a large
hydropower site of, say, 500 MW or 1000 MW
capacity. The two principal environmental con-
cerns of a small scale system are qualitative and
quantitative in character.
Qualitatively, the problem is site specific.
Many sites with potential for small scale develop-
ment are unique in some other way which may
be seriously affected. That is, although the site is
small and the facility will be small, the environ-
mental impact of the development may be signifi-
cant because of the special ecological or other
role of the small stream or family of streams or
even family of drainage basins. Most of my
discussion has focused on qualitative impacts.
The important factors here are 1) who renders
the judgement of the stream’s unique rote and 2)
upon what information was that decision made.
Although these factors won’t be discussed here,
the subjects of who makes environmental deci-
sions and upon what information the decisions
are based are important and should be clearly
understood in implementing any resource
development program.
An example of the qualitative character of
small scale development is the small streams in
New England (U.S.) that are the spawning
grounds for Atlantic salmon. Efforts are currently
underway to reestablish thtat fishery. Since
salmon will only spawn in the stream where they
were hatched, the environmental quality of these
small headwater st:eams are cirtical. Develop-
ment could eliminate a considerable fraction of
the salmon population.
In the case of quantitative concerns, the ques-
tion is one of scope of activity. One might ask,
“If the capacity of a 500 MW plant is 500 times
greater than that of a 1 MW plant, does it follow
that the environmental impacts are also 500
times greater ?” On an individual basis, small
scale projects may be relatively harmless com-
pared with a large scale project. However, in the
case of a program involving 500 sites of, say an
average of 1 MW capacity each, the impact could
be quite significant. The reason for this is that
the impacts of these 500 sites tend to
accumulate with other existing conditions
to form an impact greater than the sum of its
parts. These cumulative impacts are also known
as incrementa! impacts or loss by attrition.