With the study areas set, the sampling procedure was determined. Several factors were considered when designing the procedure including quality assurance / quality control (QA/QC) for field sampling and other outside influences. The study period was from winter 2006 to the winter of 2007. During that time period the exact precipitation dates differ between the individual locations.  The Red Lake samples were collected at the home of Leland Coe in Tenstrike, Minnesota.  Marty Peisch in Brainerd, Minnesota collected the samples for 30 Lakes on her dock located on the north shore in the west bay of North Long Lake.  The Shell Rock Watershed District decided to collect samples at two locations.  The first location was at the Court House in Albert Lea, Minnesota and the second location was at the home of Emily Bartusek also in Albert Lea. The following list details the procedure followed at all sampling locations.

1. At the start of the study, three individual Gallon size Ziploc bags were labeled Dry Bag, Sample 1, and Sample 2 along with the date placed.
2. A large rock or other form of anchor was placed in the bottom of each collection container (between the sampling bag and the bottom of the container).
3. The labeled bags were placed into each container unzipped and attach with 4 binder clips.
4. All three collection containers were placed on a dock or in open areas away from trees.
5. Prior to each rain event the “Dry Bag” was zipped shut.
6. Both sample bags were labeled with the rain event date and all required information was recorded on the data collection sheet provided.
7. Once the rain event had concluded all sample bags were frozen and the pitchers were reset with new bags including a new dry bag, which was left unzipped until the next storm event.
8. Samples were either delivered or shipped frozen to A.W. Research Laboratories for analysis.

Image 2 – collection containers

When all samples were received by the laboratory, further processing of the samples was conducted.  For each sample bag a volume measurement was determined.  The volumes of sample bag 1 and sample bag 2 were averaged to determine the volume of distilled water used in the processing of the dry bag sample.  An acid washed graduated cylinder was used to measure out the specified dry bag volume and was then added to the gallon Ziploc labeled dry bag to produce a wet dry bag sample.

The study protocol required that all rain event samples were to be tested for total phosphorus and filtered total phosphorus based on available volume.  In order for the laboratory to analyze the samples for total phosphorus and filtered total phosphorus, minimum volume of 100 ml and 200 ml were required respectively.

Data collection sheets accompanied each storm event and were used to generate the HYSPLIT graph. The following was recorded on each collection sheet.

Sample information:

§         Date the sample bag was placed

§         Date and time dry bag was closed

§         Start date and time of storm event

§         End date and time of storm event

§         Date sample bags or wet bags were closed

§         Inches of precipitation

Storm event information:

§         Altitude of cloud base

§         Type of precipitation

§         Characteristics of storm event

§         Outside natural disasters

Majority of the time, the cloud base altitude was not recorded and occasionally the start time of the storm event was not recorded or was unknown.  For each location, a weather observation station was used to complete the information on the data collection sheets.  When the cloud base altitude was not recorded the temperature and the dew point temperature from the observation station at the start of the storm event were used to calculate the cloud base altitude.