Transition to fall, new managers, project completions
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From the Administrator

Welcome to fall!

This time of year, the lakes and creeks around the district are more beautiful than ever, and we hope you have a chance to get out and enjoy the scenery. 

At this change of seasons, the watershed district is also in a place of transition. In August, we welcomed two new managers to our board: David Ziegler of Eden Prairie and Larry Koch of Chanhassen. They represent Hennepin County and Carver County, respectively, and will help us implement the goals and policies of this district. Our two high school interns finished up their service with the district and are off to college, and University of Minnesota Service Learners began volunteering with us in mid-September. Our newly formatted website is getting closer and closer to a public launch. Work continues of district projects, education and outreach, data collection, and resource monitoring.

We also continue to plan ahead to our 50th anniversary celebration in 2019, and hope that you will come celebrate with us! There will be many opportunities to join in the fun. We'll be at the Lake Ann Winter fest (Winter), host a walking challenge to explore the district (Spring), host a public celebration of our community (Summer), and pedal a 10- 20- or 50- mile bike ride (Autumn). Our 50th anniversary photo contest will open later in October 2018, and remain open through October 2019. 

We are proud of all of the work that that we accomplished this summer, grateful to all who collaborated with us, and looking forward to a great fall season.


District Administrator

Dr. Claire Bleser

Featured event

Community Clean Up for Water Quality, October 27th, 9:30am- noon.

Saturday, October 27
9:30am- noon
(Rain date Sunday, October 28th)

Do your part to keep our favorite lakes and streams clean! The City of Chanhassen and the Riley Purgatory Bluff Creek Watershed District are hosting a community clean-up for water quality. We are looking for volunteers to rake, sweep, or shovel leaves, dirt, and debris from curbs and streets before they enter our water. Come help, have fun, and get to know your neighbors.

This is a great opportunity for families, groups, or individuals! Learn more and sign up to volunteer at

Phosphorus is a major source of water pollution that causes algae blooms and depletes oxygen needed for fish and native plants. It often comes from decaying organic matter such as leaves, branches, and loose dirt.  When it rains, streets, parking lots, and other impervious surfaces provide a pathway for phosphorus to get to local lakes, rivers, and streams. By doing your part to clean up our streets, you’ll help ensure these pollutants don’t reach lakes and streams.

Other Upcoming Events

Coming soon:

RPBCWD Photo Contest!

The rules
  • Photos must be taken in the district any time in 2018/ 2019 
  • Max. 10 submissions per photographer 
  • Must know the names and contact info of all identifiable people in the photo. 
  • Photos must be: 
    • horizontal format/ orientation
    • at least 300dpi
    • TIF, JPEG or PNG format (digital photos only)

Submitting your photos
Visit to submit your photos starting October 22nd, 2018

Winners will have their photos published in the RPBCWD 2020 Calendar!
We are looking for photos from all seasons, featuring lakes, streams, recreation, wildlife, plants, or anything else outdoors that catches your eye.

Project Updates

Alum treatment on Lotus Lake And Rice Marsh Lake

In September, alum treatments were completed on Lotus Lake and Rice Marsh Lake. Application company HAB Aquatics applied 108,000 gallons of alum at Lotus Lake and 33,000 gallons of alum at Rice Marsh Lake in a precise, uniform, and safe manner. 

Alum reduces the growth of algae by trapping the nutrient phosphorus - algae’s food source - in sediments. Like most other plants, algae require phosphorus to grow and reproduce, so less phosphorus means less algae. An alum (aluminum sulfate) solution is applied underwater by a specially mechanized barge. When it mixes with the water, it forms a fluffy aluminum hydroxide precipitate known as "floc." As this floc sinks through the water, it binds with phosphorus in the water column and traps it down in the lake sediment. The primary purpose, however, is to bind to phosphorus already in the lake bottom, and to keep it from releasing up into the lake. Alum is a common lake restoration treatment, and is safe. It does not pose any known risk to humans, pets, or wildlife.

These treatments come after a long preparation process involving the reduction of external phosphorus entering the lakes, measurements of water quality and phosphorus concentrations in the lake bottom, and calculations to accurately dose the amount of alum applied to each lake. Moving forward, RPBCWD Staff will continue to assess water quality and phosphorus concentrations. Lotus Lake and Rice Marsh Lake are scheduled to receive the second half of this split-dose treatment in 3-5 years, depending on how they respond to the initial application.

Thank you to Wenck Engineering, HAB Aquatics, the City of Eden Prairie, and the City of Chanhassen for their work and support on the project. More information about these applications can be found at and


Volunteering Opportunities

Volunteer newsletter

An updated issue of our volunteer newsletter will be released later this week! To receive newsletters, update your email subscription preferences to include volunteer opportunities. 
Other opportunities with partners & friends
  • Wetland Health Evaluation Program (Hennepin & Dakota Counties) Wetland Health Evaluation Program (WHEP) is an environmental monitoring program focusing on assessing the condition and health of wetlands. Join a team of other interested citizens who are concerned about wetlands in your area. Teams are organized and named after their sponsoring city or watershed location. More info
  • Citizen Assisted Monitoring Program (Metropolitan Council) A volunteer lake-monitoring program. More info

News From the Field

Sampling for Macro-invertebrates

In September, District staff worked with staff from the Metropolitan Council to sample for aquatic macro-invertebrates in Purgatory Creek. At the test site, they collected stream water samples and sent them off to Metropolitan Council labs for testing. Researchers there will identify and record the various species living in and on the water, as one means of understanding Purgatory Creek's health.

These aquatic macro-invertebrates, including aquatic insects, worms, snails, and crustaceans, are important biological indicators of stream health. Because they are particularly susceptible to minor changes in water quality, the presence or absence of certain species of these creatures can provide clues about the health of a stream and surrounding ecosystem. For example, some pollution-sensitive species such as mayflies, stoneflies, and caddisflies require high amounts of dissolved oxygen and neutral pH. Other species, including aquatic worms and midge larvae are more pollution tolerant, so a relative abundance of these animals may indicate low oxygen levels, lower/higher pH, or other chemical pollution.

The data collected in these tests will be used by the Metropolitan Council, the Riley Purgatory Bluff Creek Watershed District, and other organizations to better understand water quality and ecosystem health at Purgatory Creek. 
Copyright © 2018 Riley Purgatory Bluff Creek Watershed District, All rights reserved.
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