HomeMy WebLinkAboutTR 35337 HYDROLOGY REPORT-029 Spyglass Ranch Tract 35337
Hydrology Study
the low flows originate on natural ground, water quality treatment is not
necessary for this area. The higher storm flows are designed to discharge
into the existing 30" culvert located in Camino Del Norte. The rational
analysis indicates that the developed condition peak flow rate of Areas "H"
is less than the total pre—developed condition peak flow rate of Area 14.
It follows, consequently, that the capacity of the existing culvert will not be
exceeded and therefore no storm mitigation is required for this area.
Tables 2 and 3 provide a complete summary of the rational method
analysis for each drainage area.
Area "I"
Area "I" is a minor drainage area in the post—developed condition that
is comprised of less than three acres of roadway and manufactured slope
area. The comparable drainage area in the pre—developed, or existing
condition is Area 15, which similarly is roadway and manufactured slope
area. The low flows from this area are designed to be treated within the
catch basin via a catch basin filter or other similar water quality
treatment device. The higher storm flows are designed to discharge into
the existing 18" culvert located in Camino Del Norte. The rational analysis
indicates that the developed condition peak flow rate of Area "I" is well
within the capacity of the existing culvert and therefore no storm
mitigation is required for this area. Tables 2 and 3 provide a complete
summary of the rational method analysis for each drainage area.
Area '°J"
Area "J" is a drainage area in the post—developed condition that is
primarily comprised of natural area. The comparable drainage area in the
pre—developed, or existing condition is Area 16. Since the vast majority of
the low flows originate on natural ground, water quality treatment is not
necessary for this area. The higher storm flows are designed to discharge
into the existing 30" culvert located in Camino Del Norte. The rational
analysis indicates that the developed condition peak flow rate of Area "J" is
well within the capacity of the existing culvert and therefore no storm
mitigation is required for this area. Tables 2 and 3 provide a complete
summary of the rational method analysis for each drainage area.
Area "K"
Area "K" is a minor drainage area in the post—developed condition that
is primarily comprised of manufactured slope area near the north property
line of Spyglass Ranch. The comparable drainage area in the pre—
developed, or existing condition is Area 3. Since the developed area is less
than one acre, water quality treatment is not necessary for this area.
Storm runoff from Area "K' will drain onto the adjacent downstream
property to the north, referred to as the Eichorn Property for purposes of
this report. In the developed condition, the area tributary to the Eichorn
Property is much smaller when compared to the correlating existing
condition drainage area. The rational analysis indicates that the total
developed condition peak flow rate of Area °°K" is less than the total pre—
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