_PERMIT FILE - M1981302 ‎(24)‎

• Permit No: M1981302
• IBM Index Class Name: Permit File
• Doc Name: WATER RESOURCES
• Media Type: D
• Archive: No

overland onto the site from the southwest. Overland flow
patterns in the area are complicated by the extensive system
of irrigation ditches and laterals . These channels convey
flood waters over a portion of the area, causing shallow
flooding. Isolated areas that are above the flood water
elevation are not inundated but are nevertheless included
within the floodplain. The Urban Drainage and Flood Control
District is in the process of revising the floodplain in
this area.
The South Boulder Creek channel capacity of 1700 cfs is
about equal to the 5-year recurrence interval discharge at
the site. Flows in excess of 1700 cfs cause local flooding
• from overflow of the creek and from overland flow from the
south.
A recently-constructed flood control berm and channel directs
flood waters away from much of the proposed mining area so
that only lands east of the berm (see Figure C-1) will now be
subjected to flooding.
Water Quality. Ground water is generally of higher quality
than surface water because of the natural filtration and
• purification offered by water percolating through the alluvial
sands and gravels. Ground water at the site is well within
. the state water quality standards. The pH is approximately 7.5.
C-5