The plant provided is a “run of the river” plant with no provision for dams and regulating systems of the available flow volume rate. The Project consists of an intake of free pouring, whose main purpose is to facilitate the uptake of water and lifting strap. The Intake structure will be provided by the construction of a tyrolean weir, a 20 meters length metallic grating where the water will enter.

The water is conveyed from the intake to the 135 meters long desander basin in which most of the solid material transported by the River shall be deposited.

The water will flow through a 1,400 meters long channel up to the forebay. The upstream portion of the channel is open (200 m.); then the water flows into a 150 m. long siphon and again in an open channel for 200 m.; after that the water pass through a tunnel for 150 m. Before enter into the forebay , the water flows through an open channel for about 550 m.

The water conveyed to the forebay will enter into the penstock as illustrated in the picture above.

The power house will be realized downstream, with 2 Francis turbines for a total installed capacity of 4 MW. After passing through the turbine blades, the water will be discharged into a collection chamber below the central building. Hence a channel will return to the Jimenoa River the entire diverted water flow.

The main building will be located on the left side of the runway at about 1,400 meters downstream from the section of the intake.

The main features of “Paso Bajito” power plant are summarized in the table below

The power generated will be dispatched by the following device:

• a 6 kV medium voltage underground power line
• a substation placed near the power house, where a step-up transformer 6/69 kV connects the transmission line to the high voltage system
• a 69 kV high voltage line to connect the evacuation line to the national grid up to the centre of Paso Bajito.

Hydrology

An hydrological study of the site has been performed using the hydrologic data available from the historical series 1956 - 1998 of Hato Viejo measurement station. The duration curve estimation is a critical issue of an hydrological study, primarily in relation to the shape of the curve and to the annual average flow estimation. The flow estimation is performed based on the daily average data measured during the 43-year flow series of Hato Viejo Station. For this estimate two procedures were applied:

• A correlation coefficient between the basins and the said station has been determined, both for the Rio Jimenoa and consequently a number of common geomorphology features
• Recordings of flows were performed weekly for a period of 12 months from June 2009 to May 2010, with the aim to calibrate the flow coefficient estimate

Geology

The following information is taken from the geological survey and Environmental Impact Statement (Declaracion de Impacto Ambiental). The morphology of the region is influenced ultimately by sedimentary processes occurring throughout the Paleogene; nevertheless its current physiognomy has outlined fundamentally and continuously from the Miocene. In particular the Duarte Complex where the Project will be developed consists of a substrate composed by a Jurassic aged oceanic crust and, over which implants a magmatism of Cretaceous age, similar to that observed in oceanic plateaus. According to the study exploited by Draper & Lewis (1991) and Lewis & Jiménez (1991) the Duarte complex could be split in two different complex:

• Lower Duarte Complex: The lower unit consists of mainly metabasic rocks, greenstones, and amphibolites, partly intruded by granitoid plutons, mainly ionalite. Minor hornblende gabbros and hornblendites are considered to be genetically related to the tonalites
• Upper Duarte Complex: The upper unit consists of subschists, formed the basis of a set of metagabbros and metadiabásic dyke swarm, which passes up a sequence of shales and cherts with very thick metabasálticas intermediate layers

As far as the soil is concern, the complex Baiguate-Hondo-Auyamas-Jimenoa groups soils with very rugged topography of volcanic origin located in the Northeastern part of the Cordillera Central. The original material is usually formed by rocks containing quartz and feldspar in varying proportions which give rise to soils with similar features. The batholith intrusive rocks (tonalite) made up most of the area affected by the Project.