ASTEC
 

CONTROL OF RUNOFF BY LENGTHENING THE IÑAQUITO COLLECTOR

Population to Serve: Approx. 200,000
Level of the Study: Final design
Location: Quito - Prov. of Pichincha
Date Consultancy began: Level of Study: Feasibility: April 2004 Final design: November 2004
Date Consultancy ended: Feasibility: June 2004 Final design: February 2005
Total Contract Amount: USD $ 136,495.62
Name of associated firms: N/A
Customer: Metropolitan Sewerage and Water Supply Company of Quito (EMAAP-Q)
Description
The Iñaquito collector receives rainwater and sewage from north-central Quito, including the eastern slopes of Mt. Pichincha. The project, with a beneficiary population of 200,000, aims to optimize runoff of that water.

ASTEC, as part of the feasibility study, formulated, analyzed and designed five alternative facilities, and identified the environmental problems caused by discharging sewage from the Iñaquito collector, and the effects that this has on livability for buildings in the area, to establish the technical, economic, environmental and risk mitigation viability for each alternative.
Subsequently, and on the basis of the alternative recommended, ASTEC did final designs for the alternative selected, comprising the following elements:

  • Encased tunnel section 5 x 5 m and 510 m long, with a capacity for 150 m3/s
  • Two rapid cascades, each for a drop of about 100 m
  • The buffering pits: first at the outlet of the conducting tunnel, 20 m long; second at the end of the first rapid cascade, 25 m long; and third at the end of the second rapids, in the waterway of El Batán Gully, 25 m long
  • Protection from delivery to El Batán Gully till it joins the Machángara River
  • Fills in the bed of the El Batán Gully, to the discharge of the Iñaquito Collector, downstream to the discharge from the second rapids.
  • Formation of a layering pond in the area of the stilling pond currently under construction to receive overflow that might enter the encased tunnel if flow exceeds design volumes, for a maximum of 400,000 m3
  • Separation of sewage in the first buffer pond to conduct it to a sand trap 35 m long, a loading tank 378 m3 in volume, and penstock 0.95 m in diameter and 525 m long
  • Powerhouse located near the confluence of the El Batán Gully and the Machángara River to lodge a TURGO type 3 MW turbine, SCADA control equipment, control panels and other auxiliary equipment
  • Outside substation on one side of the powerhouse, bars, transformer and auxiliary equipment
  • Transmission line 2 km long

ASTEC @ 2009