well field and the remainder has been greatly diluted with inflowing fresh water so that the field now contains a relatively small amount of chloride--about 100 parts per million (see plate 8).
The salting of the present well field clearly .points out the danger of developing a new supply near enough to a canal that may, at times, contain salt water. Under the influence of the cone of depression surrounding the field this salt water could move into the field and contaminate
it.
Development of Additional Ground Water supplies.--In choosing the site of additional well supplies several important factors should be considered. Among these, without any attempt being made to arrange them in order of importance, are the following:
(1) Sufficient thickness of permeable aquifer
(2) Satisfactory quality of ground water.
(3) Safety from possible encroachment of salt water at depth in
the aquifer and from canals carrying, at times, sea water.
(4) Location far enough-removed from possible future developments
and activities of other interests that might interfere with
safe and continuous operations.
(5) Location consistent with shortest pumping distance to water
treatment plant and to distribution system.
(6) Location consistent with accessibility to well field area.
(7) Proper spacing of wells so that a minimum cone of depression
will develop.
Earlier in this report factors (1), (2), and (3) have been generally discussed. At this point it would be pertinent to p6iit out, that in an area about seven miles wide (see plate 6), measured west from the present well field, and extending northeast and southwest roughly paralleling the shore .ine, a well field might be developed almost any