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ig through the equipment arsenal <br />of most citizen volunteers monitor- <br />ing Minnesota streams, and you'll <br />likely find a long, clear plastic tube, that looks <br />like it comes from a mad chemist's dreams. <br />This device, called the transparency tube (T- <br />tube), is used to measure water clarity or <br />transparency in a stream. It is cheap to make <br />or buy, relatively simple to use, and most <br />importantly, has taken on new significance in <br />Minnesota. <br />The big news: Transparency tube <br />data will be used for determining turbidity <br />impairments for the first time during the <br />2006 assessmem of Minnesota's streams. <br />What does this mean for assessments? <br />Every two years the Minnesota Pollution <br />Control Agency (PCA) is required to report <br />to Congress and the Environmental <br />Protection Agency, on the condition on <br />Minnesota's lakes and streams. This report, <br />known as the 305(b) Assessment, includes <br />turbidity measurements that are compared to <br />Minnesota's water quality standards.. If a cer- <br />tain number of turbidity measurements <br />exceed the water quality standard, then the <br />stream is listed as impaired. <br />Transparenry (water clarity meas- <br />ured by T-Tubes) is closely linked with tur- <br />bidity. This means that transparency tube <br />readings are good predictors of the turbidity <br />(cloudiness) of the water. When a stream <br />transparency reading is below 20 centimeters, <br />the turbidity standard is exceeded. PCA has <br />developed specific criteria for using trans- <br />parency tube data in the turbidity assessment <br />process, based on transparency and turbidity <br />data that were collected across Minnesota over <br />the past 6 years (see next page for criteria). <br />What does this mean for citizens? <br />It means that data collected by trained citi- <br />zens will be used at the state level to help <br />determine impairment of waters. Currently <br />only eight percent of Minnesota's streams <br />have been assessed for water quality. By <br />establishing a scientiFically-based link <br />between transparency and nubidiry, more <br />- - <br /> <br /> <br />y..i Yt~~ <br />x,. ~. h @ h. ~, of R W. i p h s <br />'Y'T.!"2'~~ <br />~; ' <br />fi <br />~v <br />~ <br />.:. `',~ Fi , <br />t <br />t. a <br />.. <br />i <br />a ~, m <br />" <br />r <br /> <br />- ,a <br />-: <br />- - o <br />~ <br /> <br />~.~- ~_ <br />a <br />~, <br />° <br />~° <br /> <br />,~ ~ <br />_ <br />o <br />- . ~, ~ ~ <br />~~ o <br />~ <br />.a <br />~ t <br />_ - a <br />streams can be assessed using citizen help. For <br />the 2006 assessments, it is estimated that <br />approximately 200 new stream segments will <br />be assessed for turbidity impairment by using <br />volunteer collected transparency data. <br />Pot more information on the T-tube assess- <br />ments, visit Rivers Council of Minnesota's <br />website: <br />www. riversmn.org/Graphics_Media_04/ttub <br />e04.pdf <br />For questions to the Minnesota Pollution <br />Control Agency, please contact: <br />Laurie Sovell, MPCA, <br />651-296-7187 (Metro area) <br />or I-800-657-3864 (Greater Minnesota). <br />~~ ~~ <br />"The big news: <br />Transparency tube <br />data will be used for <br />determining turbidity <br />impairments for the <br />first time during the <br />2006 assessment of <br />Minnesota's streams." <br />Page 6 <br />Angie Becker Kudelka, <br />RIVER WATCH DIRECTOR, RIVERS COUNCIL OF MINNESOTA <br />and Laurie Sovell, MINNESOTA POLLUTION CONTROL AGENCY <br />