Review of environmental monitoring methods: survey designs

During the past decade and a half, environmental monitoring programshave increased in numberand importance. Large scale environmental monitoring programs often present design difficulties because they tend to measure many(sometimes hundreds) of parameters through space and time. Thispaper reviewed and summarized one important component of environmental monitoring programs, the statistical survey design. Survey designsused for long-term monitoring programs lasting multiple (3)occasions were reviewed, paying specialattention to those published after 1985. During this review, two key components of the overall survey design were identified. The first key component wasthe membership design. Groups of population units sampled the same occasionwere called panels here, and the membership design specified which units were members of which panels. The second component was the revisit design that specified when panels were to be revisited. Membership designs varied, butsome form of simple random or systematic design was popular.Among revisit designs, four basicpatterns were found in the literature and their relative strengths andweaknesses were summarized. To efficiently discuss revisit designs, anew unified short-hand notation was proposed and adopted.