Golden Lake Project Water Quality Improvement Project

2019 marked the completion of a large scale water quality improvement project designed to removed excess nutrients form stormwater prior to it discharging into Golden Lake. Golden Lake is located in the City of Circle Pines and has been designated as being impaired by nutrient contamination. Excess nutrients lead to high algae growth and low water clarity. This project was completed by a partnership of the City of Circle Pines ($70,000) and the Anoka Conservation District ($12,000) with financial contributions from the Rice Creek Watershed ($50,000) District and the Clean Water Fund of the Clean Water Land and Legacy Amendment ($467,968)

Although it looks like little more than a sand volley ball court, the project relies on precise chemistry and physics. The project pumps water from a stormwater pond just upstream of Golden Lake and directs that water through a sand filter that is enhanced with iron filings. The iron filings chemically bind to the nutrient pollution. The clean, filtered water discharges to an old ditch alignment that goes to Golden Lake. When functioning per the design, the project should remove 40-60 pounds per year of phosphorus for 25 years, which gets us 50% of the way to our goal for Golden Lake.

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ACD Receives Grant for Abandoned Well Sealing Cost-share Program

In Anoka County, 330,000 residents (94% of the population) depend on groundwater for drinking water, using about 12 billion gallons annually.

In 2015, Anoka County identified more than 2,300 properties in Drinking Water Supply Management Areas (DWSMAs) that have a high potential of having an unused/unsealed well (see map to right).These abandoned wells pose a risk to human health by providing a direct, unmaintained conduit where contaminants, such as pesticides, nutrients, heavy metals, salts, hydrocarbons, and pathogens, can be introduced into groundwater drinking water supplies.

Anoka Conservation District (ACD) was awarded a Clean Water Fund grant to coordinate a cost-share program to financially incentivize Anoka County property owners to hire licensed professionals to seal abandoned wells in high priority areas (i.e. within DWSMAs).Through targeted outreach, ACD will identify landowners interested in participating, and the program will provide funding to seal up to 125 abandoned wells.


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ACD Awarded a State Grant for Carp Mgmt. at Linwood & Martin Lakes

A State grant has been awarded for carp management at Linwood, Martin and Typo Lakes and is set to begin in 2020. This $148,000 grant is funded through the Clean Water Fund and will build on the successes of the current carp management program. Contributions from the Martin Lakers Association, Linwood Lake Association, and the Sunrise Watershed Management Organization will assist in funding the grant. ACD will be the grant recipient and help coordinate partnerships between private contractors, volunteers, and local organizations. The state took notice of the success the current program is having and saw that continuing work in this area of Anoka County should be a priority, ranking the project #3 out of nearly 100 applications statewide​.

Carp management over the last 3 years, funded by a different grant, was able to remove enough carp from the lakes to reach the halfway mark of the total reduction goal. Similar techniques will be continued over the next 3 years. A private contractor will develop management plans specific to each lake. Large box-nets will be installed in priority areas and be baited with bags of cracked corn. Throughout the season the nets will be harvested by the contractor and local volunteers. The nets will be maintained by residents who live near the harvesting sites and ACD staff​.

Carp populations have the ability to grow quickly and can be devastating to overall lake health if left unmanaged. This grant is focused on improving water quality, help reduce seasonal algae blooms and improve the habitat and life cycle for other game fish.

This grant is the fruition of hard work and support from many individuals and organizations. By continuing to plan and build strong local partnerships, these lakes are on track to meet management goals and prevent carp population increases that would likely cause declining water quality.

If you live on Linwood, Martin or Typo Lakes and would like to learn more about the program or would like to inquire about volunteering, please contact the ACD office. (763) 434-2030.

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2019 ACD Monitoring Season

2019 was another successful monitoring season for The Anoka Conservation District (ACD). Strong partnerships with watershed districts, watershed management organizations, and local lake associations, allowed ACD to implement a variety of monitoring programs including; daily precipitation totals (12 volunteers), lake levels (25 lakes), lake water quality (11 lakes), stream hydrology (12 sites), stream water quality (18 sites), stream benthic macroinvertebrates (3 Anoka County schools), shallow groundwater levels in wetlands (19 sites) and deep groundwater levels in observation wells (24 sites).

2019 ended up being the wettest year on record for the state of Minnesota with a state-wide average of 35.51 inches, breaking the previous record of 33.93 inches set in 1977. Due to the banner year Minnesota had with rainfall, we saw historically high water levels in lakes and streams and higher than average groundwater levels in many wetlands and groundwater wells. 2019 was a great year for overall water quality, with many of the lakes and streams showing improvements compared to the historical average.

With a growing population and ever-increasing development, it is more important than ever to have the ability to make informed decisions when it comes to land use management and for local leaders to have an understanding of how those decisions may affect natural resources. Water resources are rapidly declining in quality and quantity throughout the metro. Anoka County is fortunate enough to still have many pristine natural areas but it will take a team effort to keep them that way.

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Rum River Central Regional Park Riverbank Stabilization

The Anoka Conservation District partnered with Anoka County Parks to stabilize 310' of eroding riverbank within Rum River Central Regional Park. Prior to the project, the bank was severely eroding and undermining sections of a paved trail. The stabilization project is now complete and included the following elements:

  • Minimal riprap at the bottom of the slope within the zone of frequent water level fluctuation where vegetation does not grow well,
  • Grading above the riprap to the top of the slope (3H:1V), seeding with native vegetation, and installation of an erosion control blanket,
  • Relocation of the paved trail to ensure sufficient separation between the trail and the new top of slope, and
  • Dormant willow stakes were installed in November 2019 as the final phase of the project.

Stabilization of the bank will prevent 100 tons of sediment annually from entering the Rum River. Multiple State and local funding sources were used to complete the project.

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Lessard-Sams Outdoor Heritage Council Recommends Funds for Rum River Stabilization Projects

The Lessard-Sams Outdoor Heritage Council is recommending $952,000 from the Outdoor Heritage Fund for ACD to stabilize eroding Rum Riverbanks utilizing habitat-building, bioengineering approaches over the next three years. Bioengineering techniques stabilize and armor eroding riverbanks in a way that both protects the bank from further erosion and provides traversable habitat for wildlife. These techniques rely on using natural materials such as tree trunks and root wads, in-stream rock weirs, native plantings and tree staking, gradual slope grading, and minimal hard armoring where necessary. Current erosion along streambanks, as well as traditional armoring techniques like riprap, result in a wall or barrier to wildlife. The bioengineering techniques that will be employed by ACD in the Rum River will eliminate those barriers and provide additional habitat for all kinds of wildlife.

ACD has identified over twenty eroding banks along the Rum River in Anoka County that it will be seeking to address with these funds. It is anticipated that four to eight sites will be stabilized with the $952,000 from the LSOHC and an additional $236,000 in local funds from Anoka County and the Upper and Lower Rum River Watershed Management Organizations. Anoka County has pledged $442,000 in Rum River stabilization matching funds over the next five years. The remaining funds will be used as match for future grant applications.

The Lessard-Sams Outdoor Heritage Council has made the funding recommendation to the Minnesota Legislature, who will draft final bill language during the 2020 legislative session. ACD will begin reaching out to landowners with identified eroding banks suitable for these stabilization techniques after the funding is finalized.

  Example photo of an eroding Rum Riverbank stabilized with bioengineering techniques. This project was the result of the continuing partnership between ACD and Anoka County Parks.

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Well and Septic Maintenance Training

Over one third of Minnesotans rely on a septic system to treat the wastewater from their homes. It may not seem so, but this is quite the responsibility! You are the owner, operator, and maintenance person for your very own wastewater treatment system found just outside your back door! Maintaining your septic system is an investment in your home and property, in your family's health, and in the health of Minnesota's abundant water supplies. A properly functioning septic system provides effective treatment of wastewater, but if a system is neglected, it could cost thousands of dollars to repair and potentially contaminate local groundwater and surface water supplies putting the health of your family and neighbors at risk.

Septic system inspections done by a licensed company at least every three years along with regular maintenance will ensure your septic system is functioning as it should and save you a lot of hassle and money. Remember that your septic system is a direct conduit to groundwater and surface water, so remain vigilant and prevent potential contaminants from entering your septic system. Even common household items like unused medication, antibacterial cleaning products, and single-use wipes can cause damage to your septic system and contaminate local waterbodies.

If you're interested in learning more about how to care for your septic system and private well, we invite you to join us for a free training from the UMN Onsite Sewage Treatment Program. The training is co-hosted by the City of Ramsey and the Anoka Conservation District and will be held on Thursday, March 12th 2020 from 5 – 7 pm in the Ramsey City Hall's Alexander Ramsey Room (7550 Sunwood Dr. NW, Ramsey, 55303). Space is limited, so reserve your seat early! Register online at https://well-and-septic-maintenance.eventbrite.com

To read more about the UMN Onsite Sewage Treatment Program, take a look at this recent article from MPR: https://www.mprnews.org/story/2020/01/10/teaching-homeowners-septic-secrets-to-protect-water

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Tips for Staying Safe in Winter

 De-icing salt is so common here in snowy Minnesota, we hardly even think before tossing it down. But we really should be thinking hard because all that salt accumulates in local streams, lakes, and wetlands causing stress and sometimes death to native animals and vegetation. Salt dissolves easily in water which means it's almost impossible to remove without expensive and time-consuming treatment. Road and sidewalk safety is a priority for all of us, so what is an environmentally conscious Minnesotan to do if they want to stay safe and minimize their salt use? Here are some tips!

Shovel First. Shovel and scrape sidewalks before they are walked on so ice doesn't have a chance to form in the first place.

Choose the Right Salt. Different chemicals work at different pavement temperatures. Be sure to choose the right one for the conditions. Sodium chloride, the most common de-icer, will only work when the pavement temperature is above 15 degrees F.

Scatter Salt Grains. Granular salt melts ice fastest when the grains are spread 3 inches apart. Contrary to popular belief, adding more salt will actually make the ice melt slower!

Sweep up Excess. If there is salt left on the ground after all the ice is gone, sweep it into a bucket to use in the next storm. You paid for it so don't let it wash away!

Pre-treat Pavement. Applying a liquid de-icer to pavement 24-48 hours before a storm will help prevent ice from adhering to the surface and make it a lot easier to scrape up.

Wear Proper Footwear. Boots with extra traction such as cleats or spikes reduce the risk that you may slip and fall. They are a worthwhile investment here in Minnesota where we're bound to encounter ice at some point.

Avoid Distractions. We all know not to drive while we're distracted. The same goes for walking! Avoid using cell phones while walking and keep your eyes on the path in front of you.

Drive for the Conditions. Here in Minnesota, there is no escaping the snow and ice. Remember that you are ultimately responsible for your own safety, so always drive with caution.

Do the Penguin Shuffle. Always anticipate icy conditions and keep yourself safe by walking on marked paths near handrails.

If you See Something, Say Something! As an environmentally conscious Minnesotan, one of the best things you can do to combat chloride pollution in our waters is to talk to your friends, neighbors, and local businesses. Pressure from residents like you can help turn the tide and protect our valuable freshwater resources now and for many generations to come.

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Minnesota's Changing Climate

Flooding in a Southwestern MN Ag. Field

Minnesota is one of the states most impacted by climate change. Official precipitation and temperature data has been collected in Minnesota from 1895 through today, showing some striking statistics about our changing climate:

  • 13% increase in the size of the heaviest annual rainfall.
  • Since 2000, rains of more than 6" are four times more frequent than the previous 30 years prior.
  • 65% increase in the number of 3" rains.
  • Average temperatures in Minnesota have warmed by 3˚F since 1895.
  • Overall, Minnesota's climate is warmer and wetter.


These changes are impacting Minnesota's wildlife, forests, water quality, infrastructure, and outdoor recreation (especially winter sports). Below are some links to MN DNR infographic GIFs that shows the change to our 30-year average winter temperature and 30-year average yearly precipitation:

 

Sinkhole in Duluth Following a 7"+ Rainfall
As you can see, Minnesota's winters are warming dramatically, with the 9˚ contour moving  north by as much as 150 miles. Similarly, the 26" contour for precipitation has migrated roughly 100 miles to the Northwest.

We witnessed the impact of elevated precipitation in 2012 when the most damaging flood in Duluth's recorded history began when heavy rains fell over already saturated ground on June 19th and 20th. At the Duluth National Weather Service (NWS) the rainfall total for those two days was 7.24 inches. A NWS volunteer observer in Two Harbors recorded the storm's largest value of 10.45 inches in 24 hours.

The aftermath included millions of dollars of insurance losses to repair roads, bridges, homes and businesses. Many homes foundations were damaged extensively and the houses were razed. One state highway (MN 23) was closed for 3 years while it was repaired. The City of Duluth has had to adapt their stormwater infrastructure to withstand events that 30 years ago were considered 500-year events, but now happen regularly. In June 2018, just southeast of Duluth, the area received up to 10" of rain and once again damaged Highway 23.

Here in Anoka County, we've witnessed a similar story in 2019, with all of the monitored lakes, rivers, and streams in the County reaching historic water level averages for the year. This increase in precipitation only solidifies the need for comprehensive watershed management to make sure that our infrastructure and waterways can handle the increased erosion and flow produced by this additional rain. 

 Interested in learning more? Check out MN Pollution Control Agency's Climate Change in Minnesota webpage or the MN Department of Natural Resources Climate Data

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291 Hits

Cut back on Salt to Protect Minnesota’s Infrastructure, Water Quality, and Aquatic Wildlife

The Twin Cities Metro applies 350,000 tons of road salt every year, but have you ever wondered where it goes when winter ends?

Stormwater and snowmelt carry dissolved road salt into lakes, streams, and groundwater when winter thaws out. Chloride, a major part of road salt compounds, is especially stubborn in water. Once it dissolves, there is no feasible method to remove chloride from water, and stormwater treatment solutions like stormwater ponds and rain gardens are ineffective at removing chloride. Instead, chloride gradually accumulates in our water bodies, harming fish and other aquatic life. The corrosive nature of road salt also contributes between $350 million and $1.2 billion in infrastructure costs each year to the Metro area alone.

What can we do about it?

Here are some helpful tips you can use to make your driveways and sidewalks safer and better for the environment this winter:

Shovel!

Salt is never a substitute for shoveling. Shovel your snow and ice first so that salt is only used for melting ice stuck to the ground.

Salt!

Traditional salt (sodium chloride) does not melt ice when the temperature is below 15 degrees Fahrenheit. Use a low-temperature alternative such as magnesium chloride or calcium chloride to melt ice at lower temperatures or use sand to add traction. There is no such thing as an "environmentally friendly" salt, so it's best to stick to salt that will work in the given range of temperatures.

Scatter!

Did you know you only need a 12-oz. mug of salt to effectively de-ice a 20-foot driveway or 10 sidewalk squares? When applying salt, aim to leave 2" between grains.

Sweep!

Sweeping up leftover salt and reusing it later is a great way to save money and limit the amount of salt getting into nearby waterways.


 Do you hire a contractor to maintain a sidewalk, driveway, or parking lot? Check out the MPCA's list of Smart Salting certificate holders to find a contractor trained on best practices for winter maintenance: https://www.pca.state.mn.us/sites/default/files/p-tr1-01.xlsx

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History and Management of the Rum River

Anoka Dam, October 1897

The Rum River is one of the largest rivers in Anoka County, second only to the mighty Mississippi. It starts at the outlet of Mille Lacs Lake and winds through the landscapes of Mille Lacs, Isanti, and Anoka Counties until it discharges to the Mississippi River in the City of Anoka—but many don't know about the progress this river has made to become one of Minnesota's most outstanding waterways.

To really appreciate the Rum River today, it's good to understand a bit of its history. For many decades, the Rum River served as a large scale aquatic conveyor for lumber. Large white pine, elm, oak, cherry, and maple all floated down the river from central Minnesota forests to build the homes and business of the growing Twin Cities Metro Area. It also conveyed our sewage, agricultural waste, sediment laden runoff, and industrial by-products downstream to the Mississippi River, and eventually the Gulf of Mexico.

A former Anoka County commissioner who grew up in the area once said that when he was a kid, no one would dare to even fish in the Rum River, much less swim in it. I'm happy to say, over the last 80 years, the fate of the Rum River has been wholly reversed. Today the Rum River is:

Martin's Landing on the Rum River
  • One of 6 Wild and Scenic Rivers and 35 State Water Trails in Minnesota
  • Designated as an Outstanding Resource Value Water
  • An excellent fishery and waterfowl corridor with abundant smallmouth bass and wood duck
  • Key reach for Species in Greatest Conservation Need

This isn't to say that our Rum River is in the clear. In the last 30 years, the population in the area draining to the Rum River has increased by 47%. With that many people came more roads, parking lots, and roof tops that added 74% more stormwater runoff. The increased water volume and speed that came with this extra stormwater caused the river to slice deeper into the landscape and rip apart the riverbanks. When riverbanks collapse into the river, the resulting sediment smothers the fish, amphibians, and reptiles that now call the river home. The Rum River is also increasingly threatened by road salt and nutrient pollution coming from this stormwater.

A Cedar Tree Revetment installed to stabilize a bank on the Rum River​.

ACD takes a holistic approach to managing these new challenges to the quality of the Rum River. We are heavily involved with monitoring the chemistry and biological quality of the River; we assist the local Watershed Management Organizations with analysis and planning; and we implement projects with willing landowners to improve water quality and habitat in the river. ACD is also involved with guiding land conservation projects near the Rum River needed to protect habitat and water quality, and we are working diligently with other local organizations to ensure future funding for projects protecting the Rum River.

Over the coming months, we will be posting short blogs to highlight individual projects and programs that ACD has directed for the benefit of the Rum River. Check in soon at www.anokaswcd.org/blog to learn more!

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579 Hits

What we wish we knew: lessons for rain garden implementation

Over the last decade the Anoka Conservation District (ACD) has been involved in the design and construction of over 100 rain gardens in Anoka County. While the overwhelming majority fall closer to the 'ideal' end of the spectrum, we've been party to a few on the 'nasty' end as well. Properly functioning rain gardens often go unnoticed because they blend in with other landscape amenities. In contrast, the small fraction of 'nasty' rain gardens get the public's attention with nasty smells and mosquito problems. Rest assured, we've learned from our mistakes, refined our process, corrected the problematic rain gardens, and can confidently say we're now able to avoid the 'nasties'.

The lessons learned over the years have improved every aspect of rain garden location, design, installation, maintenance, and follow-up. These are our suggestions for other organizations designing and installing rain gardens.

Failed rain garden that doesn't drain between rain events

Design

  • For a standard rain garden, the water table should be at least five feet below the bottom of the garden. This will require an eight-foot-deep soil boring during the design process because the bottom of the garden is often two to three feet below the original ground elevation. Rain gardens with shallower water tables are feasible, but require an underdrain to function properly.
  • Soils should have high infiltration rates, generally one to three inches per hour. Rain gardens can be built in soils with lower infiltration rates, but may require an underdrain or a ponding depth shallower than 12".
  • If an underdrain is needed, install a control mechanism that allows variable draw down rates and levels. This provides a mechanism to capitalize on natural infiltration that may increase as the deep root structure of the native plant community matures and creates pathways for infiltration.
  • Water must be able to get into the garden consistently, predictably, and without causing erosion. The curb-cut should be sized to safely pass sufficient water volumes.
  • Utilizing a retaining wall along the back of the garden can improve the aesthetic appeal and allow the garden to store more water. Rain garden side slopes should be no steeper than 3:1. Therefore, for every foot of wall height, three feet of rain garden bottom is gained. In many cases this simple addition more than doubles the size of the garden.
  • Consider using a pretreatment chamber. A pretreatment chamber functions like a filter, capturing floatables like leaves, trash, seeds, and sediment to ensure rain gardens are able to properly receive water and dry between storms
Rain garden mid-construction, with a retaining wall and intact curb
Location
  • Rain gardens should be sited where they will capture runoff from a sizeable contributing drainage area that would otherwise make it into a priority water resource.
  • They should treat stormwater that isn't already routed to a stormwater pond or other installation for stormwater management.
  • They should be strategically located on properties where they will quickly fill during storms and quickly drain between storms.
  • They need to be located where they won't interfere with utility lines. Utility companies have minimum cover requirements over lines that may not be met following rain garden excavation. While some utilities like cable lines can be moved or lowered for a relatively low expense, others like gas and electrical lines can be cost-prohibitive to relocate when they conflict with the proposed rain garden location.
  • If a rain garden is installed in an area where the road routinely floods over the curbs, water will flow into the rain garden over the sides and cause erosion. It will also result in deeper water than intended, which will take longer to drain out.
  • If a rain garden receives water from a large neighborhood with non-natural runoff sources like irrigation systems or sump pump discharge, the rain garden may never have the chance to drain completely.
Rain garden pretreatment chamber

Installation

  • Curb-cut rain gardens are one of the few conservation practices where landowners volunteer to use their property to treat runoff from other properties. The landowner volunteering contributes relatively little to the problem and benefits relatively little from the solution. They also commonly assume maintenance responsibility for 10 years. For these reasons, local government should consider covering 100% of the construction costs.
  • Avoid equipment traffic within the garden.
  • Check soil infiltration rates. If they are under the design specification, loosen soil throughout the
  • garden with a four-foot auger.
  • Plant gardens in the spring and early summer, not in the fall.
  • Lay no more than three inches of mulch.
  • If possible, consider leaving the curb intact until the plants are established and then complete the curb-cut. Minimally, when installing a curb-cut rain garden as a retrofit, leave the curb intact until the basin is completed. This ensures the basin is stable and ready to receive runoff as soon as the curb-cut and apron are installed.
  • Install informative temporary signage during construction and permanent signage upon project completion that explains the value and function of the rain garden.
Ideal rain garden

Maintenance

This is a list of suggestions that can be provided to a homeowner after installation:

  • Get your neighborhood involved! If your neighborhood has several rain gardens, try to schedule a periodic neighborhood cleanup day.
  • Mulch will break down and should be refreshed every couple years.
  • Stay on top of weeding. Err on the side of pulling too much.
  • Homeowners should not be afraid to experiment with the plants in their rain garden. Try using native plants to encourage pollinator presence!
  • Pretreatment chambers should be cleaned out after each rain event. This should take no more than a few minutes.
  • Remove excess leaves in the fall. Having a few leaves is great for catching sediment and creating critter habitat, but too many leaves will create mats and slow down water infiltration.
  • Regularly remove sediment that makes it past the pretreatment chamber.
Community rain garden cleanup in Anoka county

Follow-Up

  • The sponsoring local government should connect annually with homeowners to remind them of maintenance needs, expectations, and flexibility.
  • Make sure homeowners know who to call if they experience problems.
  • Consider providing a maintenance program to help with plant replenishment or other incentive to keep gardens well maintained.
  • After the 10-year life of the garden, consider a refresh. Hire professionals to remove all plants, mulch, and accumulated sediment and debris, and power wash the retaining wall and pretreatment chamber. Then, add new mulch and replant, salvaging mature plants whenever possible. This relatively inexpensive investment can buy another 10 years of function.

When done right, rain gardens are an effective and beautiful method for combating pollution in lakes and streams, replenishing groundwater, and creating pollinator habitat. However, not every property or every homeowner is ideally suited to have a rain garden. While professionals at ACD can assess whether or not a property is a viable candidate, only the homeowner can decide if they are up to the task of maintaining a rain garden.

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565 Hits

What in the World is a Rain Garden?

  Rain gardens have popped up like weeds throughout the Twin Cities over the last decade to mitigate stormwater pollution in lakes, rivers, and streams. Despite their prevalence, the function and purpose of these little curbside gardens remain a mystery for many folks.

Downspout rain garden

Rain Garden Benefits:

Cities are very dirty. When it rains, stormwater picks up everything from feces to the motor oil that your neighbors spilled on their driveway. Many older neighborhoods were developed without stormwater treatment, so pollutant-laden runoff from roads, houses, driveways, and parking lots makes its way directly into rivers, lakes, and streams. Stormwater doesn't end up in a wastewater treatment facility or septic system like the water that drains out of your bathtub.

When functioning correctly, rain gardens protect natural water bodies from polluted stormwater, reduce flooding, recharge groundwater, and provide habitat for local pollinators. Rain gardens can be built to any size or shape to fit into the landscape of old neighborhoods where space is limited. They are relatively inexpensive to design and construct and can be maintained by homeowners who agree to take on that responsibility.

To treat all of the water in a neighborhood, it may be necessary to pepper the neighborhood with many small rain gardens, or put in a few larger gardens depending on available space and landowner interest. A well-functioning rain garden will dry out within 48 hours after a rain event, which keeps the plants healthy and prevents creation of mosquito habitat.

  Rain Garden Types:

There are two basic types of rain gardens, those built to treat water exiting a gutter downspout, and those built to treat road runoff. The first type, called a downspout rain garden, can easily be installed by a homeowner. This type of rain garden can prevent flooding around downspouts and allow rainwater to recharge groundwater.

The second type is called a curb-cut rain garden because an opening is cut into a roadside curb to allow water to flow off the road into the rain garden. When the rain garden has filled to the brim, the stormwater flowing along the curb will pass by and flow into the storm drain as it did prior to installing the rain garden. Curb-cut rain gardens are much larger, more complex, and should be designed and installed by professionals. Curb-cut rain gardens are more cost-effective because they only treat water that would definitely have made it into the stormwater system. For this reason, they are the only type of rain garden for which Anoka Conservation District currently provides assistance.

While traditional curb-cut rain gardens are built with the expectation that water will drain through the soil, some rain gardens are built in conditions that don't allow for water to drain quickly enough. In this scenario, an underdrain would be installed below the rain garden. The underdrain re-directs excess water from the rain garden into the street's stormwater drain to prevent the rain garden from flooding.

Thriving curb-cut rain garden that easily drains within 48 hours
Failed rain garden that does not drain between storms

Rain Garden Pitfalls:

Unfortunately, some rain gardens don't work as intended. Due to poor planning, faulty design, shoddy construction, or a lack of maintenance, some rain gardens fail to properly fill or drain. When done right, rain gardens are an effective and aesthetically pleasing method for combating pollution in lakes and streams, replenishing groundwater, and creating pollinator habitat. However, not every property or every homeowner is ideally suited to have a rain garden. While professionals at ACD can assess whether or not a property is a viable candidate, only the homeowner can decide if they are up to the task of maintaining a rain garden.
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