May 21, 2024

Point sources surpass interim goal

Eliana Brown

URBANA, Ill. — Point source and urban stormwater sectors have been making progress in meeting the Illinois Nutrient Loss Reduction Strategy goals.

The state’s NLRS long-term goal is a 45% reduction in both nitrogen and total phosphorus loads, and the short-term goal is to reduce the phosphorus load by 25% and the nitrate-nitrogen load by 15% by 2025.

A NLRS biennial report was released last month providing details of where Illinois stood in terms of meeting those goals to reduce the loss of nutrients to the Mississippi River and eventually to the Gulf of Mexico.

Representatives from the sectors included in the strategy detailed the biennial report in a recent NLRS podcast hosted by Todd Gleason, University of Illinois Extension media communications specialist.

Trevor Sample, Illinois Environmental Protection Agency NLRS coordinator, and Eliana Brown, U of I Extension water quality and stormwater specialist, dissected the point source and stormwater sectors of the biennial report, respectively, in the podcast.

What are some key points of the biennial report as it relates to the point source sector?

Sample: One of the highlights of the point source sector is that sector has achieved a combined statewide reduction of 6.2 million pounds of phosphorus from 2011 to 2022. This represents a 34% reduction, which exceeds the 25% goal by 2025 set in the Illinois NLRS.

The baseline load was 18.1 million pounds in 2011 and the total load for 2022 was 11.9 million pounds — 10.2 million pounds of that is from the 211 major municipal dischargers, 1.3 million comes from the minor municipal dischargers (about 970 wastewater treatment plant facilities) and about another 400,000 pounds comes from industrial facilities.

What are the requirements point sources are asked to reduce nutrient loss and how are those goals being accomplished?

Sample: In order for wastewater treatment facilities to discharge wastewater they have to have a National Pollutant Discharge Elimination System permit. It’s a Clean Water Act permit that Illinois EPA administers. Those permits dictate the amount and type of pollutant that can be discharged into that wastewater.

When it comes to phosphorus, right now the facilities are aiming to meet 1 milligram per liter phosphorus concentration in their discharge, and eventually that number will move to 0.5 milligrams per liter of phosphorus in their discharge.

We have 211 of what we call major municipal facilities in Illinois. These are facilities that have a design average flow of 1 million gallons per day or more. Out of the 211, 101 facilities discharge an average phosphorus concentration of 1 milligram per liter or less, and, of those, 46 are meeting a 0.5 milligrams per liter or less phosphorus discharge.

So, this is another metric that we use in showing progress from the individual point sources themselves.

Sixty-seven individual facilities are currently completing nutrient assessment reduction plans. Most of those were due Dec. 31 and the remaining are due next December. These plans are a way for facilities to show how they’re going to go about reducing phosphorus not only from their discharge, but also within the watershed itself.

Statewide point sources also have reduced total nitrogen loads by 11.6% from the 2011 baseline through 2022.

Major municipal facilities are also required to complete feasibility and optimization studies through Illinois EPA, and all of those studies have been submitted.

Looking down the road by the end of this decade, we anticipate the point source sector will achieve our long-term goal of 45% reduction of phosphorus and possibly even exceeding that.

STORMWATER RUNOFF

What is stormwater and what role does it play in the NLRS?

Brown: Stormwater runoff refers to rainfall and melted snow that doesn’t soak into the ground because it’s hitting hard surfaces like roads, roofs and parking lots. This runoff is a significant contributor to urban water pollution, carrying phosphorus, nitrogen and other things into water bodies via storm drains.

The NLRS science assessment found that stormwater’s sector impact on the overall nutrient load in the state leaving state is relatively minor compared to other sectors.

However, it still poses a threat to water quality in our local lakes are rivers in Illinois. Consequently, stormwater runoff a component of the strategy to safeguard our water quality.

What are some highlights of the 2023 biennial report as it relates to stormwater sector?

Brown: The report highlighted the engagement of the more than 8,900 participants in 121 stormwater management events during 2021-2022 which underscores the widespread community involvement.

The Metropolitan Water Reclamation District of Greater Chicago played a major role in stormwater management, investing $1.45 million in green infrastructure program projects, thereby increase retention capacity by more than 500,000 gallons. Their overall commitment for 2021 stormwater program amounted to $44.7 million.

Illinois EPA’s Green Infrastructure Grant program awarded $5 million to support 11 stormwater projects in 2021, resulting in the retention of 1.2 million gallons of stormwater and a reduction of pollutants.

They also had 14 urban stormwater best management practices covering 174 acres. Those were implemented through the Illinois EPA Section 319 grant.

The Illinois groundwater website, established in 2021-2022, provides green infrastructure research, tools and resources to stormwater professionals, local leaders and community members. There’s also a green infrastructures inventory map that showcases nearly 2,000 stormwater best management practices across the state.

How do you define green infrastructure and what role does it play in reducing nutrient loss?

Brown: Green infrastructure captures that stormwater runoff that doesn’t soak in and allows it to act more like a natural water cycle, soaking in or storing it for use later. It refers to nature-based systems designed to manage water, provide environmental benefits and promote environmental resiliency.

It uses natural processes like vegetation, soil and permeable surfaces that address these water quality challenges by decreasing stormwater runoff that goes into the rivers.

Practices include rain gardens, bioswales, permeable pavement, green roofs, cisterns and constructed stormwater wetlands.

Tom Doran

Tom C. Doran

Field Editor