Visual impact assessment of small dock & piers: Theory and practice

From a manager’s perspective, oftentimes the publicly held concerns related to small docks and piers are not really related to the environment. They may be more related to visual impacts and aesthetic concerns, a sense of over-development of the shore, or simply change. While individuals may hold personal aesthetic values related to small docks in general or an individual structure in particular, techniques have evolved that appear to provide reproducible, predictive assessments of the visual impacts and aesthetic values of an area and how those might change with development, including an increase in numbers of small docks. These assessments may be used to develop regulatory or non-regulatory methods for the management of small docks based on state or community standards. Visual impact assessments are increasingly used in the regulatory review of proposed development—although this process is still in its infancy as regards small docks and piers. Some political jurisdictions have established visual impact or aesthetic standards as relate to docks and others are in the process of investigating how to go about such an effort. (PDF contains 42 pages)

Selectivity of Metsulfuron Methyl to Six Common Littoral Species in Florida

Many Central Florida lakes, particularly those in the Kissimmee River watershed, are maintained 0.5 to 1.0 m lower than historic (pre-1960) levels during the summer hurricane season for flood control purposes. These lower water levels have allowed proliferation and formation of dense monotypic populations of pickerelweed ( Pontederia cordata L.) and other broadleaf species that out compete more desirable native grasses (Hulon, pers. comm., 2002). Due to the limited availability of data on the effects of metsulfuron methyl on wetland plants, particularly in Florida, the present study was carried out with the objective of testing its phytotoxicity on six wetland species, to determine the feasibility of its use for primary pickerelweed control.

Evolution of the tectogene concept, 1930-1965

The tectogene, or crustal downbuckle, was proposed in the early 1930s by F.A. Vening Meinesz to explain the unexpected belts of negative gravity anomalies in island arcs. He attributed the isostatic imbalance to a deep sialic root resulting from the action of subcrustal convection currents. Vening Meinesz's model was initially corroborated experimentally by P.H. Kuenen, but additional experiments by D.T. Griggs and geological analysis by H.H. Hess in the late 1930s led to substantial revision in detail. As modified, the tectogene provided a plausible model for the evolution of island arcs into alpine mountain belts for another two decades. Additional revisions became necessary in the early 1950s to accommodate the unexpected absence of sialic crust in the Caribbean and the marginal seas of the western Pacific. By 1960 the cherished analogy between island arcs and alpine mountain belts had collapsed under the weight of the detailed field investigations by Hess and his students in the Caribbean region. Hess then incorporated a highly modified form of the tectogene into his sea-floor spreading hypothesis. Ironically, this final incarnation of the concept preserved some of the weaker aspects of the 1930s original, such as the ad hoc explanation for the regular geometry of island arcs.