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In this paper, I develop a model where “exploration” yields information about the size and location of the stock of an exhaustible resource. This information is valuable in two ways. First, before production takes place, reserves must be located through exploration. The process of exploration changes “unproven reserves,” which cannot be produced, into “proven reserves,” which can. One value of exploration, then, is that it allows total production over time to expand (the expansion effect). Second, by exploring in an early time period, a producer gains information about the true stock size prior to making a decision about how fast to exploit reserves. With better information, the extraction rate chosen by the producer...
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The Upper Midwest Environmental Sciences Center of the U.S. Geological Survey and its state partners monitor the aquatic vegetation as well as fish, water quality, and macroinvertebrates in the Upper Mississippi River System. The objective is to accumulate data on aquatic vegetation over a long term using a standardized protocol across the system. The data provide basic information on the vegetation growth within pools for use by resource managers and planners as well as the public for the protection and enhancement of the Upper Mississippi River System. This report summarizes the annual stratified random sampling monitoring results of aquatic vegetation in the Upper Mississippi River System.
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In 2003, the format of the annual reports was changed to a Web-based annual update where all years of data are presented in each table. Links to older vegetation status reports are below:
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Aquatic vegetation was investigated in five navigation pools in the Upper Mississippi River System using a new protocol named “stratified random sampling” or SRS protocol for the first time in 1998. The five pools were Pools 4, 8, 13, and 26 of the Upper Mississippi River and La Grange Pool of the Illinois River. The results on submersed aquatic vegetation and rooted floating–leaf aquatic vegetation were summarized in this report. The percent frequencies of submersed aquatic vegetation in shallow water areas (≤ 3 m deep at flat-pool condition) in the five pools were 36.6%, 47.6%, 42%, 6.1%, and 0%, respectively. The aquatic area strata that were directly influenced by the flow in the main channel, such as the main...
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The Upper Midwest Environmental Sciences Center of the U.S. Geological Survey and its state partners monitor the aquatic vegetation as well as fish, water quality, and macroinvertebrates in the Upper Mississippi River System. The objective is to accumulate incremental data on aquatic vegetation over a long term using a standardized protocol across the system. The data form a core base for use by resource managers and planners as well as the public for the protection and enhancement of the multiuse of the Upper Mississippi River System. This report is designed for Web publishing of the annual monitoring results of aquatic vegetation in the Upper Mississippi River System using a stratified random sampling protocol...
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