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Pond Dredging 101 : Don't get stuck in the muck The need... he stormwater pond on Indian toxic in nature that require special fees and You dig? Oaks Court is City property and disposal in landfills. D elair Excavating was selected and currently helps control runoff from D made quick,efficient work of the the surrounding neighborhood.After The soils tested at the Indian Oaks Court pond dredging.They took careful atten- years of accumulated sediments,many project tested at Level 1.In conjunction tion to not disturb the natural pond bottom stormwater ponds,including this one, with the pond dredging,the project calls under the stormwater sediment."They now require maintenance.While many for shoreline restoration and plantings did a wonderful job,"added Von Holtum. of these ponds are on City property,they to satisfy BMPs as well as beautify the "They kept the street clean and respected can affect nearby property owners as the neighborhood. the adjacent neighbors and their proper- water levels continue to rise and the water ties."From start to finish,the dredging quality declines due to increasing levels Resident participation took nearly two weeks to complete, of sediment."We were beginning to deal L`d Van Holtum,whose property is however,there remains a few items to be more and more with erosion issues,and directly behind the pond,took action finished,including shoreline restoration ducks could barely swim in the water,we that helped his neighborhood become the and planting which will occur sometime knew something needed to be done about first pond restoration project."We got in this spring. Plant material serves as the the pond,"says Ed Von Holtum,a resident touch with the local watershed district preliminary water treatment buffer,before that lives adjacent to the pond. who supplied a list of projects in Ramsey the runoff enters the pond.You have prob- County for us to drive by and check out." ably noticed rain gardens peppering the The set up After data had been gathered,the project landscape,as they too are a stormwater The Minnesota Pollution Control Agen- information was brought initially to the management BMP,generally on a smaller cy(MPCA)has - scale. set forth guidelines on many issues _ t Working smart related to stormwa- �� hile pond dredg- ter management,and # ; = Wing projects in the inspection of the City appear im- ponds is a require- minent,the City has ment under the MS4 4 adopted some smart Permit.Flowcharts management practices developed to follow to reduce the amount best management of future maintenance practices(BMPs) to ponds: "The amount help cities determine of accumulated sedi- the maintenance ment has been reduced schedule of storm in recent years with water ponds.For the absence of sand in example,there are ~ ' our ice-melting appli- steps for inspection cations,"stated Terry and sampling water Maurer,Public Works and sediments,and Director."That saves on how to determine street sweeping and dis- when sediments should be hauled away Public Works Director for review and then posal cost."Moving forward,the Ramsey and disposed of or recycled. If a pond con- to the City Council for final approval.The Conservation District provided technical tains excess sediment,the recommended participation of Von Holtum and other assistance for the restoration aspect of this BMP is to perform a dredging process to residents adjacent to the pond helped project,while the Roseville Engineering remove such sediment and possible toxins reduce City staff time and ultimately Department put plans and specifications that may reside in the muck. Soil testing is helped save tax dollars."It is easier to go together for the pond excavation phase.A preformed on the to-be dredged materials into a neighborhood when the residents letter was written to the Ramsey Conser- to determine if they are contaminated with have shown interest in the maintenance of vation District requesting cost-share funds, polycyclic aromatic hydrocarbons(PAHs) their ponds,"adds Terry Maurer,Direc- along with required project data.Ryan or heavy metals. for of Public Works."When residents get Johnson of Ramsey Conservation District involved,people have a better idea of assisted with the landscaping plan and There are three levels of concentration. the process and it makes everyone's job cost-share forms used for the project. Level 1 is the safest,where soils could es- easier." sentially be readily used in the landscape as fill,etc.Level 3 involves soils more 4 Continued on page 5