San Francisco’s $4.4-billion Hetch Het­chy Water System Improvement Project has passed a major milestone with the approval of its program environmental impact report. The San Francisco Public Utilities Commission began planning for the program, consisting of 85 projects, in 2002 to improve the system’s ability to op­erate in the aftermath of a major earthquake. The program is funded by a bond issue approved by voters in 2002. Construction of many smaller proj­ects has proceeded while the report was being com­pleted on 17 larger sections valued at $1.8 billion. Construction on many major projects will begin in the next six to 18 months, says a commission spokesman.