Bulletin 1.pdf - California Department of Water Resources - State of ...

li4 WATER RESOURCES OF CALIFORKIA
sources. Runoff of excellent quality from the Santa Lucia Range commences
earlier in the season and is better sustained than inferior quality
runoff from the Diablo Range. Until about 1925, when irrigated acreage
in Salinas Valley was approximately half the present, average runoff
from the Santa Lucia Range occurring early in the season was sufficieut
to recharge fully all ground waters in Salinas Valley, except in minor
deltas of east side streams south of King City. Consequently there was no
remaining capacity in the ground water basins for retention of inferior
quality drainage from the Diablo Range. However, heavy draft on
ground waters in dl")· years since 1925 has increased retention of poor
quality waters from the Diablo Range and resulted in enlargement of the
zone of comminglement.
Ground waters recharged from drainage of the Santa Lucia Range
vary in quality from excellent to good, while those recharged from
commingling of drainages range from good to fair, and those recharged
from Diablo Range drainage, from fair to unusable. The first eleven
analyses for Salinas Valley gi,·en in Table 41 are of ground waters
recharged from Santa Lucia Range drainage. The following seven are
of ground waters recharged from commingling of drainages. The last six
are of ground waters recharged from Diablo Range drainage. The latter
are unsafe for irrigation use because of excessive salinity, excessive
l"hlorides, or excessive boron.
Quality of ground waters in Arroyo Grande Valley, and in small
basins along the coastal strip to the north in San Luis Obispo County, is
generally good, except in minor areas of sea water encroachment. These
are l"arbonate type waters, and calcium and magnesium are rather
ewnly balanced as the important bases.
In Santa Maria Valley the ground water is similar in quality to water
of Santa Maria River, which contains a blend of high concentrations of
sulphates from Cuyama River and low total solubles from Sisquoc River.
Ground water in Sisquoc Valley generally reflects the good quality of
water in Sisquoc River, and that in the vicinity of Lompoc is similar to
water in Santa Ynez River.
All constituents in ground waters of Sisquoc and Santa Ynez Valleys
are rather evenl)' balanced, and total salinity is moderate. Ground waters
in the south coastal strip of Santa Barbara County in the vicinity of
Carpinteria are calcium carbonate type, and generally low in total
solubles.