Browsing by Author "Arika, Caleb N."

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    Implementation of Methodology for Weed Management Practices
    (Minnesota Department of Transportation, 2009-02) Arika, Caleb N.; Nieber, John L.; Wyse, Donald L.; Moon, Roger D.
    A study initiated in 2004/2005 in District 4 of Mn/DOT compared the use of 100 1/4-mi long segments against seven 3-mi segments on sampling precision for the estimation of weed infestations in highway rights-of-way for Canada thistle (Cirsium arvense (L.)(Scop.), leafy spurge (Euphorbia esula L.), and poison ivy (Toxicodendron radicans). The comparison showed that the 3-mi and 1/4-mi plans yielded equivalent estimates of mean weed population density, although the results indicated that at the district level precision was greater with the 1/4-mi plan. Further investigations suggested that additional improvements in precision and efficiency would likely occur if segment lengths were shortened to 125’ or less. The project implementation phase reported here aimed to investigate efficiencies of two sampling plans, one with weed density measured over 100, 225-ft segments, and one with presence/absence of weeds measured over 150, 14-ft segments. Results showed that the presence-absence surveys almost consistently underestimated the area infestation derived from the 225-ft surveys. The 14-ft survey required substantially less time to conduct, but at this time they appear to be less precise than the 225-ft surveys with regard to quantifying infestation density. It is recommended that an additional season of survey data be analyzed to better quantify the precision of the 14-ft survey results.
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    Implementation of Methodology for Weed Management Practices – Phase II
    (Minnesota Department of Transportation, 2009-09) Arika, Caleb N.; Wyse, Donald L.; Nieber, John L.; Moon, Roger D.
    In 2008 a Phase II implementation project was conducted to test whether presence/absence surveys could provide accurate and cost effective estimates of invasive weed species infestation in roadway rights-of-way within Mn/DOT District 4. A 225-ft survey, in which infested areas were mapped, was used as the standard for comparison to the presence/absence surveys which were conducted using 14-ft ‘stick walks’. A 2007 Phase I project had shown the presence/absence surveys to be more cost effective, but the infestation estimates were consistently lower than the standard. The 2008 study provided additional data to test the efficacy of the presence/absence surveys. The results of the 2008 study showed that the presence/absence surveys were significantly less costly than the standard, but the estimates of infestation themselves were not satisfactory relative to the standard scheme. From this study it is concluded that surveys should be conducted using the 225-ft sampling scheme for invasive species that form contiguous patches. The lower cost of the presence/absence surveying scheme might make it a good option for sampling of invasive weed species infestations for the case of rare species such as poison ivy which do not typically form contiguous patches.
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    Subsurface Drainage Manual for Pavements in Minnesota
    (Minnesota Department of Transportation, 2009-06) Arika, Caleb N.; Canelon, Dario J.; Nieber, John L.
    A guide for evaluation of highway subsurface drainage needs and design of subsurface drainage systems for highways has been developed for application to Minnesota highways. The guide provides background information on the benefits of subsurface drainage, methods for evaluating the need for subsurface drainage at a given location, selection of the type of drainage system to use, design of the drainage system, guidelines on how to construct/install the subsurface drainage systems for roads, and guidance on the value of maintenance and how to maintain such drainage systems.