Recommendations

The recommendations in a nutshell are to address the zones with flooding at all moderate rain events.  In addition, we recommend following up on two specific areas that we have the best evidence to find where the system connects to the engineered storm drain system as apparent in the as-builts. We also firmly believe that the investment in the underground should be augmented by a top down approach of replacing the existing gutters and downspouts so that gutter guards can be applied; and since most of the downspout elbows have been damaged by landscaping equipment over the years the replacement would be prudent. 

Downspouts in this zone are in PVC and flushed better than corrugated piping.  This zone has a breach near a tree at the corner where the sidewalks meet.  It is recommended to replace this section of pipe and remove the root network within a reasonable buffer.  

This is one of the worst zones.  This zone has flooding throughout, especially in the corner.  There is a pop out  and larger pipe network that never receives water no matter which downspout is flooded.  We recommend full replacement of the lines with PVC and to do further discovery on where the pop out piping leads. the pop out is approximately where the yellow hexagon is drawn,

This zone has a section where the collector is above grade that should be buried.  There is also a section common in several zones where bushes were planted directly next to the downspout connection to the underground corrugated,  These two lines should be replaced completely by combining into one downspout and shifted to a new downspout route identified nearby.  This zone also was traced close to the parking lot, where it should be excavated as a discovery exercise to determine how the zones connect to the engineered storm water system. The location of this line is indicated with the purple circle. 

This zone is all PVC and feeds to the parking lot surface directly and requires no further attention. 

This zone is all PVC and spills onto the parking lot surfaces and no further work is recommended. 

This is one of the worst performing zones with heavy flooding near the building corner present at even light downfall events.   It is recommended that there is a full replacement of this zone. Several downspouts do not connect directly to the underground system at all.  There is the bush condition that should be rerouted.  This would also allow for a discovery of how the current system in the front of the building connects to the engineered storm water system. 

This zone is likely connected to Zone #1 and it is worth discovering whether this zone connects to the same collector in zone #1 that appears to go under the parking lot to reach the engineered storm water system.  This zone also has the sam bush condition that requires a reroute, and an additional downspout not connected to the underground system at all.  It is recommended that this zone receives a full replacement.