Volunteers conducting cleanups alongside Denver’s South Platte River encounter all kinds of cast-offs alongside its banks: buying carts, meals wrappers, weapons — even obscure relics like automotive telephones from the Nineteen Nineties.
Whereas a brand new period of river revitalization tasks and riverside growth plans is taking maintain, water high quality usually stays beneath state requirements. Some sections of the South Platte nonetheless stink. And regardless of a promise by former Denver Mayor Michael Hancock to make the river swimmable, metropolis well being officers nonetheless warn in opposition to going within the water — particularly in the course of the summer time months.
“If you wish to go swimming, go to a swimming pool — you’re a lot safer there,” stated Jon Novick, the Denver Division of Public Well being and Atmosphere’s water high quality program administrator.
The current swell of consideration on the South Platte — by builders, group leaders and metropolis officers working to enhance situations — has highlighted the various environmental challenges nonetheless current.
Wastewater crops discharge effluent into the river, and corporations similar to Suncor Vitality launch a variety of drugs into the South Platte and the streams that stream into it. Amongst them: inorganic nitrogen, arsenic and the category of PFAS compounds often known as “ceaselessly chemical substances.”
Denver’s well being division for many years has tracked a swath of contaminants in addition to river situations. The division displays water temperature, acidity, vitamins and metals.
However the division’s largest concern is E. coli micro organism, which might trigger infections or sicken individuals if ingested, Novick stated. E. coli can enter the water by animal or human waste. Denver’s ageing infrastructure implies that typically wastewater pipes leak sewage, which finally reaches the river, he stated. All the metropolis’s stormwater flushes to the South Platte.
The micro organism spreads quicker within the hotter waters of summer time, which is when persons are probably to need to take a dip. E. coli concentrations enhance because the river flows downstream to the north.
In its most up-to-date water high quality report, printed final October, the DDPHE ranked South Platte water high quality as “honest” — above “marginal” and “poor,” however beneath “good.” E. coli ranges exceeded the Colorado Water High quality Management Fee’s customary year-round in 2022. The river additionally exceeded requirements for arsenic, which is of course occurring within the bedrock below the town.
The river additionally suffers from the byproducts of the tens of millions of people that reside close by. Something on Denver’s streets and sidewalks not blown away or picked up finally makes its method to the river: trash, garden fertilizers, runoff from roads, pet waste, oil and grease from automobiles.
A part of the Mile Excessive Flood District’s work is to assist native governments higher clear stormwater earlier than it reaches the river.
The district — based within the wake of Denver’s catastrophic 1965 flood — has tracked some optimistic tendencies within the river’s well being. Vitamins like phosphorus and nitrogen have typically declined, stated Holly Piza, the district’s analysis and growth director. The vitamins from merchandise like fertilizers could cause algae blooms and damage aquatic ecosystems.
However different water high quality points are worsening, she stated, together with salinity — which hurts aquatic life and may harm infrastructure.
Makes an attempt to mitigate the issue throughout Denver embrace a set of bioretention ponds exterior the Carla Madison Recreation Heart on Colfax Avenue. These assist retain water after rainfall and filter it by the filth, as a substitute of permitting all of the water to stream instantly towards the river.
Novick and Piza urge Denverites to be extra considerate: Don’t use fertilizers with phosphorus or nitrogen. Don’t litter. Wash your automotive at a automotive wash. Be sure that sprinklers are watering grass, not pavement.
“There’s a ton the town is doing to enhance water high quality,” Novick stated, “however we are able to’t be in all places and we are able to’t do all of it.”
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