Stormwater Management and Late-Winter Chloride Runoff into an Urban Lake in Minnesota, USA
Stormwater runoff containing road deicing salts has led to the increasing salinization of surface waters in northern climates, and urban municipalities are increasingly being mandated to manage stormwater runoff to improve water quality. We assessed chloride concentrations in runoff from late-winter...
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MDPI AG
2025-03-01
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| author | Neal D. Mundahl John Howard |
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| description | Stormwater runoff containing road deicing salts has led to the increasing salinization of surface waters in northern climates, and urban municipalities are increasingly being mandated to manage stormwater runoff to improve water quality. We assessed chloride concentrations in runoff from late-winter snowmelt and rainfall events flowing into an urban Minnesota, USA, lake during two different years, predicting that specific stormwater drainages with greater concentrations of roadways and parking lots would produce higher chloride loads during runoff than other drainages with fewer impervious surfaces. Chloride levels were measured in runoff draining into Lake Winona via 11 stormwater outfalls, a single channelized creek inlet, and two in-lake locations during each snowmelt or rainfall event from mid-February through early April in 2021 and 2023. In total, 33% of outfall runoff samples entering the lake collected over two years had chloride concentrations exceeding the 230 ppm chronic standard for aquatic life in USA surface waters, but no sample exceeded the 860 ppm acute standard. Chloride concentrations in outfall runoff (mean ± SD; 190 ± 191 ppm, <i>n</i> = 143) were significantly higher than in-lake concentrations (43 ± 14 ppm, <i>n</i> = 25), but chloride levels did not differ significantly between snowmelt and rainfall runoff events. Runoff from highway locations had higher chloride concentrations than runoff from residential areas. Site-specific chloride levels were highly variable both within and between years, with only a single monitored outfall displaying high chloride levels in both years. There are several possible avenues available within the city to reduce deicer use, capture and treat salt-laden runoff, and prevent or reduce the delivery of chlorides to the lake. |
| format | Article |
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| spelling | doaj-art-61567846ba5446dba74ee2d8d7c371e72025-08-20T02:28:28ZengMDPI AGHydrology2306-53382025-03-011247610.3390/hydrology12040076Stormwater Management and Late-Winter Chloride Runoff into an Urban Lake in Minnesota, USANeal D. Mundahl0John Howard1Ecology and Environmental Science Program, Department of Biology, Winona State University, Winona, MN 55987, USANatural Resources and Sustainability, Engineering Department, City of Winona, Winona, MN 55987, USAStormwater runoff containing road deicing salts has led to the increasing salinization of surface waters in northern climates, and urban municipalities are increasingly being mandated to manage stormwater runoff to improve water quality. We assessed chloride concentrations in runoff from late-winter snowmelt and rainfall events flowing into an urban Minnesota, USA, lake during two different years, predicting that specific stormwater drainages with greater concentrations of roadways and parking lots would produce higher chloride loads during runoff than other drainages with fewer impervious surfaces. Chloride levels were measured in runoff draining into Lake Winona via 11 stormwater outfalls, a single channelized creek inlet, and two in-lake locations during each snowmelt or rainfall event from mid-February through early April in 2021 and 2023. In total, 33% of outfall runoff samples entering the lake collected over two years had chloride concentrations exceeding the 230 ppm chronic standard for aquatic life in USA surface waters, but no sample exceeded the 860 ppm acute standard. Chloride concentrations in outfall runoff (mean ± SD; 190 ± 191 ppm, <i>n</i> = 143) were significantly higher than in-lake concentrations (43 ± 14 ppm, <i>n</i> = 25), but chloride levels did not differ significantly between snowmelt and rainfall runoff events. Runoff from highway locations had higher chloride concentrations than runoff from residential areas. Site-specific chloride levels were highly variable both within and between years, with only a single monitored outfall displaying high chloride levels in both years. There are several possible avenues available within the city to reduce deicer use, capture and treat salt-laden runoff, and prevent or reduce the delivery of chlorides to the lake.https://www.mdpi.com/2306-5338/12/4/76salinizationroad deicing saltsurban stormwater managementlake chloride monitoring |
| spellingShingle | Neal D. Mundahl John Howard Stormwater Management and Late-Winter Chloride Runoff into an Urban Lake in Minnesota, USA Hydrology salinization road deicing salts urban stormwater management lake chloride monitoring |
| title | Stormwater Management and Late-Winter Chloride Runoff into an Urban Lake in Minnesota, USA |
| title_full | Stormwater Management and Late-Winter Chloride Runoff into an Urban Lake in Minnesota, USA |
| title_fullStr | Stormwater Management and Late-Winter Chloride Runoff into an Urban Lake in Minnesota, USA |
| title_full_unstemmed | Stormwater Management and Late-Winter Chloride Runoff into an Urban Lake in Minnesota, USA |
| title_short | Stormwater Management and Late-Winter Chloride Runoff into an Urban Lake in Minnesota, USA |
| title_sort | stormwater management and late winter chloride runoff into an urban lake in minnesota usa |
| topic | salinization road deicing salts urban stormwater management lake chloride monitoring |
| url | https://www.mdpi.com/2306-5338/12/4/76 |
| work_keys_str_mv | AT nealdmundahl stormwatermanagementandlatewinterchloriderunoffintoanurbanlakeinminnesotausa AT johnhoward stormwatermanagementandlatewinterchloriderunoffintoanurbanlakeinminnesotausa |