Water In, No Water Out: How a Rain Garden at Gary City Hall Cut Stormwater Runoff

Urban stormwater — rain and snowmelt that isn't soaked up by lawns and other pervious ground, plus runoff from the roads, roofs and parking lots packed into cities — can cause flooding, overwhelm sewage treatment plants and pollute streams and lakes. Green infrastructure — engineered features that imitate nature — can collect runoff, reduce it and clean it up.

In 2014, Gary, Indiana, began using green infrastructure to protect Lake Michigan and its tributaries. From November 2016 to June 2017, the mostly paved parking lot in front of Gary City Hall was torn out and rebuilt around a rain garden, and the U.S. Geological Survey (USGS) measured the result.

A soaking June 2020 storm: parking lot runoff flows into the rain garden, where it will soak into the soil, be taken up by plants or recharge groundwater instead of entering the sewers. USGS

Location of the Gary City Hall study site. USGS

Why it matters

In the Great Lakes watershed, stormwater drains either straight to lakes and streams or to treatment plants that discharge into them. Too much of it brings flooding, sediment, warmer water, less oxygen, damaged habitat and lost fish, along with contaminants such as metals, nutrients, bacteria and organic compounds. But good data on how well green infrastructure actually performs have been scarce. Since 2014, the USGS and the EPA have monitored green infrastructure in several Great Lakes cities (see all the sites).

How a rain garden works

A rain garden is a shallow depression that holds runoff for a while as it soaks into the ground or evapotranspires — evaporating from the soil or being taken up and released by plants. The soil beneath is replaced or improved with a mix that drains well and suits deep-rooted plants. At Gary, native plants both draw moisture out of the soil and make the lot more attractive. Many communities encourage rain gardens with workshops and grants, including federal programs.

Cross-section of the Gary City Hall rain garden. USGS

Before and after

Until 2017, runoff from the lot drained through a pipe into the city's combined storm and sanitary sewer under Massachusetts Street. It was treated at the sewage plant — or, when storms overwhelmed the plant, likely mixed with sewage and discharged into Lake Michigan's tributaries.

Gary City Hall in 2016, before the rain garden. David C. Lampe, USGS

After the rain garden was built, 2017. USGS

In 2016, the USGS installed equipment to record runoff, groundwater levels and weather; after construction, five more stations tracked water entering and leaving the garden. Monitoring ran through the warm months of 2016, 2017 and 2018, and the data — rainfall, sewer discharge and evapotranspiration — fed annual water budgets for the lot.

![At night, an employees dressed in safety yellow in the rain garden leans over a small
metal box that has the drain grate removed, and it is full of water. The e](https://media.hubnx.com/asset/9ac05acc2ecd087d8ef1ebaf001d4ed5fd82a70bbc633d7d3ea600d208a4fbd4.png?Policy=eyJTdGF0ZW1lbnQiOlt7IlJlc291cmNlIjoiaHR0cHM6Ly9tZWRpYS5odWJueC5jb20vYXNzZXQvOWFjMDVhY2MyZWNkMDg3ZDhlZjFlYmFmMDAxZDRlZDVmZDgyYTcwYmJjNjMzZDdkM2VhNjAwZDIwOGE0ZmJkNCoiLCJDb25kaXRpb24iOnsiRGF0ZUxlc3NUaGFuIjp7IkFXUzpFcG9jaFRpbWUiOjE3OTEyNDE4MDd9fX1dfQ__&Key-Pair-Id=K1CWAV4W62RI0D&Signature=iLgS2I7zbG79ZfwbMvMAMoiRI5T2mNU42dQJB7ycOEIsvROzPALMwsm7KHyBStMwrTr5NUXuPFHsT9NVU~C2Gj3MmvTLBpJmvh9v4ryzvDoU1yUES1wrJut0VEpE6tETDbUKYhWZf2RInwT1Dt~a6SB6oKeF6cjQcMMCQgWduBTCJQf4fuffQfC0OGSLzOCR9jUgRpA5grmDcbMjfZ0Z1spift6rbcl39zN7pLEC-sXkKWr08apGuB8Wl-kuLaKa6JsbAQLEIN6v6Xv4PmQxo1RQfZqZv00s2UJUiUHHkcpJ9CgOJc77qRmTr0DhzQAeRmIJhYC94w4EbtOFNARx7g__)

*A U.S. Geological Survey scientist collecting a chloride sample from a rain garden
flume.*

![A man stands on a ladder working on a piece of equipment attached to a tower with
monitoring equipment](https://media.hubnx.com/asset/acf7971371eaae5680befd13593aa653ef859143eb14543c93f4d9431d48948c.png?Policy=eyJTdGF0ZW1lbnQiOlt7IlJlc291cmNlIjoiaHR0cHM6Ly9tZWRpYS5odWJueC5jb20vYXNzZXQvYWNmNzk3MTM3MWVhYWU1NjgwYmVmZDEzNTkzYWE2NTNlZjg1OTE0M2ViMTQ1NDNjOTNmNGQ5NDMxZDQ4OTQ4YyoiLCJDb25kaXRpb24iOnsiRGF0ZUxlc3NUaGFuIjp7IkFXUzpFcG9jaFRpbWUiOjE3OTEyNDE4MDd9fX1dfQ__&Key-Pair-Id=K1CWAV4W62RI0D&Signature=JzvaAzODlFnDSKfcx9J5YjkeSk1iE4w6C6d49FzAK4lcymIRaURPYdo93DUMf4q3HwdcLFTny7EqW84VKOZ2FE-dMbpBamvdUEJDiVOCVbeJ4WjoA4~64iFTgCreGG09k6~LnGciTYIoCcSQ6mNrBwArOG1f~BZ6T989lGGPd9VmGTrfZkUQGOwuteDnj-apLPc6a11gvX2PzCIGhRIEolTUUrkN7YCUDIpZCPNboZIOUOdpDIu4w57jDzCKH9vv~nJM5tqnf-GXIXhn8VBqcdzmLYycvif1PVZaWL14sC4ELZbaXyqbJXffYaGMiEDGd1J324y3Q3WNITQCtTxN9w__)

*Figure 5.Photograph of installation of a weather station that recorded rainfall, air temperature,
and potential evapotranspiration at Gary City Hall, Gary, Indiana, 2016. Photograph
by David C. Lampe, U.S. Geological Survey.*

The rain garden and monitoring locations at Gary City Hall. USGS

What they found

The rain garden nearly eliminated runoff to the sewer, cutting it by 80.3% — about 21,400 gallons less in 2017 and 39,300 gallons less in 2018. Most of the rain was held in the garden until it evaporated, was used by plants, or recharged groundwater.

Green infrastructure, in other words, can effectively reduce stormwater discharge.

Sources

Based on Becky Hammer-Lester, "Water in, no water out—How a rain garden reduced stormwater at City Hall in Gary, Indiana," U.S. Geological Survey Fact Sheet 2026–3012, USGS; a work of the United States government in the public domain. It summarizes Lampe, Bayless and Follette (2022), Stormwater reduction and water budget for a rain garden on sandy soil, Gary, Indiana, 2016–18, USGS Scientific Investigations Report 2022–5101, and cites Baker and others (2022), the Great Lakes Commission (2018) and the EPA. Pictures an earlier version of this page left out were restored on 2026-09-26.