15 Monitoring Blog for Site 96 October 2012 EWB Erosion Control

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Tech Monitoring Blog for October 2012 Erosion Control Minga Project Area = Will Mahoney's Site 96

Site 96 is a drainage immediately north of Malinguapamba with an eroding scarp uphill from the road and gully (riochuelo) downstream. EWB-guided Minga last October installed rock revetment, check dams, drop structures, cutback slopes, laid in erosion control blankets, and planted shrubs.

(Profesor) Ignacio Sacatoro told me it was very dry for first couple of months but there has been recent rain and we saw good evidence of significant runoff.

Overall great success downstream from road, comparing photos it looks like all BMPs remain in place with no new downcutting or flanking. In fact, the channel downstream from road is now collecting as much as 25 cm new sediment which in turn reduces stress on banks but sandy texture limits pioneering plants. Lowest BMP is pretty much full and sand is being diverted to river-left (descending) and highwater would spread out and overflow along the entire lower perimeter which is good. Could this lower perimeter be planted with lechero?

Vegetation good in channel including 95% survival rate for shrubs in channel, but less survival (60%) up on banks.

Field trip with Octavos (8th Grade) was fun and my first chance to speak as Profe Geoff!

NOTE that livestock do not roam free here in Ecuador but are instead tied up to a stake which keeps their impacts localized and in this case out of project area.

Also NOTE need to balance sediment input from upstream scarp and collection in project area. For instance, another "lift" of check dams would fill up quickly and bring invert upward. My sense is upstream scarp could be stabilized pretty easily with low-profile check dams + vegetation.

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