HomeMy WebLinkAboutTR 35337 HYDROLOGY REPORT-010 Spyglass Ranch Tract 35337
Hydrology Study
that is adjacent to Tract 31593, also referred to herein as "South Shore."
Each of these areas will be addressed throughout the report as they relate
to the post—developed conditions under the ultimate condition, interim
condition, or both scenarios when applicable. Following is a brief
description of these three edge conditions in their existing states.
Firstly, to the southwest, there are five identifiable drainage areas that
are intercepted by existing culverts located along the frontage road, Camino
Del Norte. The series of culverts along Camino Del Norte are maintained
by the City and are designed to capture flows generated from the site,
then convey them under the I-15 Freeway, then along the westerly side of
the I-15 Freeway towards the Wasson Canyon Basin, and then into the Lake
Elsinore Channel. The areas tributary to the existing culverts are
identified in the Existing Condition Hydrology Map as Areas 12 through 16,
inclusive. Table 1 lists each drainage area and the culvert it discharges
into.
Table 1: Existing Culvert Drainage Areas
Drainage Area Designation Existing Culvert Description Node
12 54" CSP 1213
13 36" ACP 1.301
18" AC P
14 30" ACP 1403
15 18" CSP 1502
16 30" ACP 1603
Notes:
1. Node numbers reference the Existing Condition Hydrology Map.
The 54" culvert inlet is a concrete headwall structure located at an
existing drainage course near an existing access road. The other smaller
culvert inlets are grated inlets generally located along the toe of slope at
the project's frontage that are designed to intercept runoff from the site
that drains off of the road slopes. The 36" and 18" culverts designated as
nodes 1305 and 1308, respectively, confluence just downstream of their
inlets at node 1.031, as reflected in Table 1.
Secondly, there is an existing 61x5' RCB culvert located in Camino Del
Norte approximately 700 feet northerly of the Spyglass Ranch west project
boundary. The inlet to the RCB is a concrete headwall structure that is
located at the frontage of the downstream property, PM 30985, and is
maintained by the City. This RCB culvert extends beneath Camino Del
Norte and the I-15 Freeway and connects to a 54" reinforced concrete pipe
(RCP) near the Wasson Canyon Channel at Collier Avenue, just upstream of
the Wasson Canyon Basin. PM 30985 indicates an approved design flow rate
for the RCB culvert of 168 cfs at the inlet within its property, and 185 cfs
downstream of the two minor catch basin lateral connections that occur in
Camino Del Norte just downstream of the inlet. The majority of this flow
is generated by an existing drainage course that enters PM 30985 from its
east boundary through the Spyglass Ranch property. The drainage area
within Spyglass Ranch that is tributary to this drainage course is identified
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