Site Drainage Design by MTUD for Los Pinos del Sur, Santa Cruz de la Sierra, Bolivia

CE 4905 Senior Design Summer 2004
Slide Show Scenes of 2004 Projects

Purpose
MTUD (Michigan Technological University Drainage Group) went to Bolivia with the intention of alleviating the flooding problems of Los Pinos del Sur, a small city within Santa Cruz Bolivia.

Problem Statement
Clay-rich soil mined to make bricks created a low spot
This low spot is in the neighborhood of Los Pinos where people live and children play.
Ditches surrounding the community do not properly drain the water.
During the rainy season, the water can reach approximately 2-3 feet deep on the street and in houses.
Water is contaminated by poor sewer systems, which causes many problems socially, economically, and environmentally.

Option One: Storm Sewer

This design consisted of two lines with three manholes:

-One down Moscu Avenue
-Another intersecting the main line from the interior of the neighborhood.

Option Two: Ditch Design

This design featured a few improvements to the current ditch as well as some other features:

-Re-grade the ditches to provide constant down slope.
-Installing culvert to drain the interior of the neighborhood
-Alternate: Swale cut across the road to the culvert
-Remove the berms blocking drainage into the culvert along the Sixth Ring
-Install wing walls on the culverts crossing University Canal Road to prevent erosion
-Backfill the culverts crossing University Canal Road
-Re-grade interior roads so that they allow water to flow toward the drain in the interior

Cost Analysis for the Storm Sewer:

This graph supports MTUD’s decision to use the 50-year storm. It is the most cost effective to use this storm because the pipe size needed for the 10, 25, and 50-year storms are the same. This is because the design pipe size for both lines in all three design storms falls between the same available accommodating pipe sizes. More simply said, the next pipe size up to hold the flow for each storm is the same.

An analysis was done for 2, 5,10, 25, 50,and 100 year frequency curves

Cost Analysis for the Ditch Design:

While MTUD was in Bolivia, some of the ditch design was actually constructed. This cost analysis shows the portion of work completed and the portion left to be completed. This cost analysis includes labor, materials, and equipment costs. The neighborhood will not have to come up with the total amount however because the City of Santa Cruz has donated some material and equipment which will drastically reduce the cost. Also, most of the labor is provided by the citizens of Los Pinos themselves.

Item	Work To be Completed	Work Already Completed	Total Cost
Backhoe (digging)	$924.00	$616.00	$1,540.00
Backhoe (loading)	$864.00	$96.00	$960.00
Dump truck	$240.00	$80.00	$320.00
Grader	$0.00	$540.00	$540.00
General Laborers	$17.00	$51.00	$68.00
Survey Crew/Equipment	$0.00	$2,000.00	$2,000.00
Culvert Sections	$0.00	$1,070.00	$1,070.00
Miscellaneous	$0.00	$40.00	$40.00
Total	$2,045.00	$4,493.00	$6,538.00

After reviewing the cost analysis for both designs, MTUD determined that it would be better to go with the ditch design. Our client does not have the opportunity to borrow money therefore we assumed an interest rate of 0.0%. Over 50 years the ditch design would be less to construct and maintain and it had a much lower initial cost.

© 2004 Michigan Technological University
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