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Ecuador Dispatches, Jan/Feb 2001

Report on Bahia de Caraquez Hillside Erosion Suitable for Revegetation Using Plantings Without Physical Alterations of the Landscape


Click on map for larger version.

(Rio Chone Border From Astillero to Kilometro Ocho Excepting El Toro Watershed)

January 23, 2001
By Peter Berg

The area of Bahia de Caraquez that borders Rio Chone from Astillero to Kilometro Ocho is backed by a long series of eroded hillsides that drain into the river and bay. The principal erosion was initiated by deforestation and grazing over decades, but recently made massive by El Nino mud slides and an earthquake in 1998. This report addresses the suitability of using only plantings with native species of grasses, bushes and trees to assist in controlling future erosion and fulfill other purposes.

A model for this type of revegetation in the area exists in Maria Auxiliadora barrio where mud slides destroyed a dozen houses and killed sixteen people. Exclusively native plants have been used there to assist in erosion control, provide an urban corridor for the endemic neotropical dry coastal forest, and create an urban park with stairways and paths named "El Bosque en Medio de La Ruinas" (The Forest in the Ruins).

The focus of this report is the portion of eroded land that is remedial using only plantings without physical alteration of landscapes such as terracing or removing tops and sides of hill. Although this represents only about one-half of the total eroded area, it is the author's opinion that the remainder will be unduly expensive to undertake while failing to ultimately provide the land stability that would be intended. Because of the lack of structural geological elements in the subsoil, terracing can actually lead to greater future erosion. Removing tops and sides of hills will alter water drainages in ways that could prove disastrous.

The watershed of El Toro creek has been excepted from this report because it covers an extensive area inland from the border of Rio Chone. This is an important feature of the whole area but deserves its own survey and revegetation program even though it ultimately funneled into part of the same region covered by this report.

The following survey was accomplished in two field trips, one in September 2000 and the second in January 2001. Peter Berg, Director of Planet Drum Foundation, and Ivan Aguirre of Bahia de Caraquez Department of Public Works made estimations using a truck that followed the main highway and sometimes drove on side roads. (For this reason, the survey may underestimate the geographical area involved by as much as thirty per cent [30%] which might have been visible on foot.)

Stations of Observation and Land Area Estimates

Estimates of land areas were made from the following points of observation. 

A) Calle 3 Noviembre

Behind and above Armada building (actually north slope of La Cruz). Nearly perpendicular area about sixty meters wide consisting of one hectare. Not treatable.
At Eugeno Santos Street. Nearly perpendicular area about one hundred meters wide consisting of one and a half hectares. Not treatable.
South of street with a pump station on the corner to the curve in the road. About two hundred meters consisting of 4-5 hectares. Treatable.
South of the next street. About one and a half hectares. Crest difficult but everything below is treatable.
South of Elasco Ibarra Street. About twenty to twenty-five meters wide consisting of one hectare. Upper is treatable but lower is not.
East halfway to street that leads to Evangelistic Church. About 2 hectares. Lower is possible to just below top.
South of unnamed street to Evangelical Church. About 3 hectares. Lower is possible but because upper is not it would be in jeopardy.
South of Rudolfo Cedeno Street. About one hectare below ceibo tree on ridge. Did not slide and does not need treatment.
East to primary highway in direction of Leonidas Plaza. About 5-7 hectares. Not treatable.

B) Exit Calle 3 Noviembre

East from speed bump in primary road to Leonidas Plaza. About 7-10 hectares. Did not slide much and doesn't require much treatment.

C) Leonidas Plaza

South of Velasco Ibarra Street. About 6 hectares. Treatable except extreme top of the hill. (Observation point to see about half of area previously described from top view looking down an back to La Cruz.)
West corner of cemetery road. About 6-8 hectares. Treatable.
East to border of El Toro Creek. About 25-30 hectares. Treatable.

D) Fanca 

West border of Fanca Creek (beyond El Toro). Bowl-shaped area of about 5-7 hectares. Treatable in 3-4 hectares.
Behind Fanca II settlement. About 15-20 hectares. Treatable in 5 hectares; some intact vegetation.
North of Fanca I and Fanca II settlements. About 15-20 hectares. Treatable in 5 hectares; some severe damage.

E) Kilometro 5 1/2 to 8 

Km 5 1/2. About 10-15 hectares. Not treatable.
Km 6. About 7 hectares. Treatable in 2 hectares.
Km 6 1/2 (Saiananda). About 6 hectares. Treatable in 2 hectares.
Km 7. About 6-8 hectares. Not treatable.
Km 7 1/2. About 6 hectares. Treatable.
Km 8. About 12-15 hectares. Treatable.
North toward Rio Chone from highway. About 20-25 hectares. Treatable in most part; 2 hectares not treatable.

Estimation of Total Land Area and Amount Treatable Through Plantings Alone

Total Area: 160-198 hectares
Treatable: 97-115 hectares
Not Treatable: 63-83 hectares

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