AUSTIN: HISTORIC HYDROLOGY RIVER TYPOLOGY AND FLOODPLAINS TODAY
A
AUSTIN IS LOCATED IN SOUTHEAST MINNESOTA, ABOUT A 2 HOUR DRIVE SOUTH OF THE TWIN CITIES. IT IS LOCATED IN MOWER COUNTY, BORDERING IOWA.
USTIN’S LOCATION AT THE HEADWATERS OF THE CEDAR RIVER, AND ALONG 2 MAJOR SUB-WATERSHEDS, TURTLE CREEK AND DOBBINS CREEK, TELL A DAUNTING STORY. THE 3 RIVERS AND WATERSHEDS COME TO A CONFLUENCE IN PROXIMITY OF WHAT WERE MANY DAMS ALONG THE RIVER. AS HISTORY WILL SHOW, ONLY 3 DAMS WOULD SHOW THE TEST OF TIME. MANY WERE WIPED AWAY FROM HISTORIC STORMS AND FLOODING, AND SOME REMOVED IN HOPES TO REDUCE THE IMPACT OF THE RIVER. THE FUTURE OF AUSTIN MAY BE UNKNOWN, BUT HOPEFULLY FROM RECOGNITION OF THE PAST, AUSTIN CAN LOOK TOWARDS A SAFER, HEALTHIER, AND PROSPEROUS FUTURE. CEDAR RIVER DAM
RAMSEY MILL DAM
FLOODPLAIN 100YR FLOOD 500YR FLOOD
STREAM TYPE ”DA”: <0.5% SLOPE MULTIPLE CHANNELS WELL VEGETATED FLOODPLAINS, WETLANDS OVER THE LAST 30 YEARS THE STORMS TO HIT THE REGION HAVE BECOME LARGER AND MORE FREQUENT. FLOOD MITIGATION OVER THE LAST DECADE HAS REDUCED THE IMPACT ON THE COMMUNITY AND PRIVATE PROPERTY. ZONING ALONG THE FLOODPLAIN AND 100 YEAR MARKS HAS MOVED FROM HOUSING AND COMMERCIAL TO PARKLAND. THIS STEP HAS PAVED THE WAY TO CHANGING AUSTIN FROM A CITY BUILT ON THE RIVER TO A CITY BUILT WITH THE RIVER.
STREAM TYPE ”A”: 4% - 10% SLOPE, MEDIUM WIDTH/ DEPTH RATIO STREAM TYPE ”E”: <2% SLOPE LOW GRADIENT, LOW WIDTH/ DEPTH RATIO
STREAM TYPE ”A”: 4% - 10% SLOPE, MEDIUM WIDTH/ DEPTH RATIO
STREAM TYPE ”A”: 4% - 10% SLOPE, MEDIUM WIDTH/ DEPTH RATIO
MILL POND 1938
RAMSEY MILL POND WAS COMPLETED IN 1872 JUST 2 MILES NORTH OF THE MILL POND ON THE CEDAR RIVER. LIKE THE MILL POND AND ITS DAM, THIS TOO WAS OWNED BY HORMEL. LIKELY MOTIVATION FOR OWNERSHIP OF 2 DAMS IN SUCH CLOSE PROXIMITY WAS CONTROL OF THE WATERWAY AND ICE HARVESTING IN THE WINTER. TODAY THE DAM IS OWNED BY THE ADJACENT RESTAURANT THAT OVERLOOKS IT. SIMILAR TO THE MILL POND, THE WATER BACKS UP CREATING THE RAMSEY POND. THIS POND IS 37 ACRES IN SIZE AND IS FED BY A 50,000 ACRE WATERSHED.
INITIALL CALLED THE 4TH AVE NE DAM, IT WAS FIRST CONSTRUCTED BEFORE THE CITY OF AUSTIN WAS OFFICIALLY FOUNDED. ORIGINALLY OWNED BY HORMEL, THIS DAM SERVED TO POWER THE LOCAL FLOUR MILL. DAMMING OF THE CEDAR RIVER IN TURN BACKED UP THE RIVER TO THE NORTH CREATING THE MILL POND AREA. OVER THE YEARS THE MILL POND WAS DREDGED MULTIPLE TIMES TO CREATE A SHALLOW “LAKE” THAT IS 5 METERS DEEP AT ITS DEEPEST, AND HAS HAD 1 TO 2 MAN-MADE ISLANDS DEPENDING ON RIVER CREST. IN THE 1960’S A NEW ROUTE FOR THE CEDAR RIVER WAS CUT, ELIMINATING A ECOLOGICALLY RICH CORRIDOR OF LAND. ON THIS LAND NOW SITS IMPERVIOUS BUILDINGS AND PARKING, ONLY EXACERBATING THE FLOODING ISSUE IN THE CITY. TODAY THE RIVER AVERAGES ABOUT 16 ACRES IN SIZE WITH A WATERSHED OF JUST OVER 50,000 ACRES.
STREAM TYPE ”E”: <2% SLOPE LOW GRADIENT, LOW WIDTH/ DEPTH RATIO
MILL POND 2015
T
HE STORY OF AUSTIN IS DEFINED BY WATER, AND ITS LOCATION WITHIN THE CEDAR RIVER WATERSHED. THE CEDAR RIVER WATERSHED STARTS IN MINNESOTA BEFORE ITS LONG MEANDERING JOURNEY THROUGH IOWA, IN SEARCH OF THE MISSISSIPPI RIVER. AUSTIN SERVES AS A CLASSIC EXAMPLE OF WHAT WE IN THE MIDWEST HAVE GROWN TO KNOW AS “RURAL”. THE CITY BEGAN IN THE MID 19TH CENTURY AFTER THE CREATION OF DAMS ALONG THE CEDAR RIVER TO AID WITH THE MILLING INDUSTRY. THE SUCCESS OF THIS INDUSTRY AND THE CONTROL OF THE WATERWAY EVENTUALLY LEADS TO A SIGNIFICANT POPULATION AND BOOM INTO THE 20TH CENTURY. INDUSTRY AND PEOPLE LIVED SYMBIOTICALLY FOR GENERATIONS, BUT NOT WITHOUT CONSEQUENCES.
MILL POND 1954
Project By: Jordan Hedlund
FEMA FLOODPLAIN DATA, GIS, MNGEOSPATIAL COMMONS RIVER TYPOLOGY REDRAWN FROM (ROSGEN, 1996, WILDLAND HYDROLOGY)
LEFT: THIS SERIES SHOWS THE DEGRADATION OF WILD NATIVE LAND TO IMPERVIOUS SURFACES AROUND THE MILL POND AND DAM. THE THIRD MAP SHOWS THE CURRENT STATE OF THE MILL POND AND LOCATION OF THE CEDAR RIVER AFTER IT WAS REROUTED IN THE 1960’S TO CREATE AUSTIN’S FIRST MALL. THIS MALL SITS IN THE FLOOD PLAIN AND WOULD CONTINUE TO BE EVACUATED FROM FLOODING REGULARLY. HISTORICAL MAPS STITCHED TOGETHER FROM MHAPO MINNESOTA HISTORICAL AERIAL PHOTOGRAPHS ONLINE
HABITAT AND HISTORY SOUTHERN TERRACE FOREST SOUTHERN MESIC MAPLE-BASSWOOD FOREST SOUTHERN WET ASH SWAMP MESIC PRAIRIE
SOUTHERN V OAK FOREST (MAPLE WOODLAND) THE ECOLOGICAL HISTORY OF AUSTIN IS STARTLING AND ENLIGHTENING. SINCE THE EARLY 1900’S, AUSTIN HAS LOST NEARLY 90% OF ITS NATURAL WETLANDS AND DRAINED OVER 21,000 ACRES ALONG THE CEDAR RIVER. MOTIVATION TO REMOVE NATURAL HABITAT WAS MANY FOLD; ONE REASON WAS TO CREATE PARKLAND LIKE HORACE AUSTIN PARK IN 1915; ANOTHER WAS TO GET RID OF WHAT WAS A “SMELLY” AREA OF THE CITY. EITHER WAY, IT IS EASY TO SEE THAT TODAY THERE IS A ECOLOGICAL VOID ACROSS THE MAJORITY OF THE CITY, THOUGH THE RIVER STILL EXISTS.
DOBBINS CREEK DAM
MCAFEE DAM (REMNANT) IN 1863, THE MOWER COUNTY MILL AND DAM WERE CONSTRCUTED OUT OF LOGS AND BOULDERS. THE DAM WAS DAMAGED IN THE EARLY 1900’S AND REBUILT MULTIPLE TIMES, BUT UNFORTUNATELY SHORTLY LIVED. IN THE WINTER OF 1936 THE DAMN WAS BLOWN UP IN HOPES THAT RETURNING THE NATURAL FLOW OF THE RIVER WOULD REDUCE FLOODING UPSTREAM. THE MILL BUILDING HAS SURVIVED TO THIS DAY.
THE DOBBINS CREEK DAM WAS COMPLETED IN 1934. SIMILAR TO THE CEDAR RIVER DAM, A “LAKE” WAS CREATED IMMEDIATELY UPSTREAM FROM IT. THE SIZE OF THE LAKE VARIES DEPENDING ON RIVER FLOW, BUT TODAY IT AVERAGES 40 ACRES LARGE THAT IS FED BY A 10,000 ACRES WATERSHED.
DNR HABITAT CLASSIFICATION, GIS, MNGEOSPATIAL COMMONS
TOP 5 CEDAR RIVER HISTORIC CRESTS TOP 5 TEMPERATURE HIGHS FOR AUSTIN
FLASH FLOOD WARNING COUNTS IN MOWER COUNTY 2003 - 2013 99 DEGREES
102 DEGREES
100 DEGREES
100 DEGREES
100 DEGREES
1978 FLOODING OF AUSTIN THE SUMMER OF 1978 WOULD TURN OUT TO BE THE 4TH HIGHEST CREST OF THE CEDAR RIVER. THIS WAS IN PART DUE TO MULTIPLE SEVERE THUNDERSTORMS OCCURRING BACK TO BACK. OVER THE COURSE OF 3 MONTHS, 3 RECORD SETTING STORMS DUMPED ENORMOUS AMOUNTS OF RAIN ON THE CEDAR RIVER WATERSHED. THE JULY 5TH FLOOD DROPPED UPWARDS OF 6” ACROSS THE NORTHERN PARTS OF THE WATERSHED IN 24 HOURS. JULY 16TH SET THE RECORD THAT YEAR OF DELIVERING 9” OF RAIN IN 24 HOURS ALONG THE CEDAR RIVER AND TURTLE CREEK WATERSHEDS. TURTLE CREEK WOULD EVENTUALLY FLOW INTO THE CEDAR RIVER AND FLOOD AUSTIN. IN SEPTEMBER, THE THIRD STORM HIT, LARGEST IN AREA, DROPPING 7” OF RAIN ACROSS THE WATERSHED. THE JULY 16TH STORM WOULD CREST THE CEDAR RIVER AT 21.9’ IN LESS THAN 24 HOURS. FLOOD DATA REDRAWN FROM NOAA HISTORICAL FLOOD ARCHIVE
SEPTEMBER 12
AFTER LOOKING AT THE HISTORICAL SPREAD OF RECORD TEMPERATURES AND RIVER CRESTS, IT IS DIFFICULT TO DENY ANY CORRELATION OF PEAKS IN THE LAST 30 YEARS. THOUGH THERE IS LIKELY LITTLE TO NO CORRELATION BETWEEN TEMPERATURE AND FLOODING IN AUSTIN, THIS DOES SHED LIGHT ON A DRASTICALLY CHANGING CLIMATE IN MOST RECENT HISTORY. 8 OUT OF THE LAST 10 HIGHEST RECORDED TEMPERATURES AND CEDAR RIVER CRESTS HAVE HAPPENED IN THE LAST 30 YEARS. FROM 1998 2013 MOWER COUNTY HAS BEEN PART OF THE FEMA FEDERAL DISASTER DECLARATION 6 TIMES BETWEEN 19982013, ALL DUE TO FLOODING AND/OR SEVER STORMS. 1998, 2000, 2001, 2004, 2008, 2010 THE CHALLENGE TODAY IS HOW DO WE ADAPT.
FLOOD STAGE AT 15’
IN A 10 YEAR PERIOD, THERE WERE 22 OFFICIAL FLASH FLOOD WARNINGS. THIS PERIOD CONTAINS THE HISTORICAL 2004 FLOOD, THAT ALSO CONTAINED THE 2ND HIGHEST FREQUENCY OF WARNINGS IN THE DECADE RECORDED.
FLOOD DATA REDRAWN FROM NOAA NATURAL HAZARD ASSESSMENT OF MOWER COUNTY, MN
FLOOD DATA REDRAWN FROM NOAA NATURAL HAZARD ASSESSMENT OF MOWER COUNTY, MN
AUSTIN 2004 FLOOD - HIGHEST ON RECORDED HISTORY
JULY 16
AUSTIN - 2016 FLOOD
16,000 CU. FT. SEC. RELEASED PEAK
JULY 5
IN SEPTEMBER OF 2004, A RECORD RAINFALL OF 12” WAS RECORDED JUST NORTH OF AUSTIN IN BLOOMING PRAIRIE. THE COMBINED WATERSHEDS OF DOBBINS CREEK AND TURTLE CREEK BOTTLE NECKED INTO THE CEDAR RIVER IN DOWNTOWN AUSTIN. FROM THIS, THE CEDAR RIVER REACHED A HISTORICAL PEAK OF NEARLY 25’, RAISING ALMOST 20’ IN JUST UNDER 24 HOURS. THE CITY SANDBAGGED TO THE BEST OF THEIR ABILITIES BUT MUCH WAS LOST. A 20-YEAR OLD AUSTIN MAN LOST HIS LIFE TRYING TO CROSS THE WATERS TO SAFETY. FROM 1995 2013 THERE WERE 18 FLOOD RELATED FATALITIES IN MINNESOTA FLOOD DATA REDRAWN FROM NOAA HISTORICAL FLOOD ARCHIVE
MINNESOTA RURAL DESIGN LAB: INQUIRIES INTO SOUTHEAST MINNESOTA O CTO B E R 2 01 9
3,400 CU. FT. SEC. RELEASED PEAK
DOBBINS CREEK
2,400 CU. FT. SEC. RELEASED PEAK
CEDAR RIVER CEDAR RIVER TURTLE CREEK
TURTLE CREEK
IN 2016 THE CEDAR RIVER WATERSHED FLOODED AGAIN, INUNDATING THE CITY OF AUSTIN. THANKS TO FLOOD MITIGATION ACTION OVER THE PAST DECADE, DAMAGE TO PRIVATE AND PUBLIC PROPERTY WAS MINIMAL AND NO LIVES WERE LOST. FROM THE MINIMAL COST TO PROPERTY AND LIVES, EMERGES WHAT TIM RUZEK FROM THE CEDAR RIVER WATERSHED DISTRICT CALLS “FLOOD AMNESIA”, AND DIFFICULTY GAINING SUPPORT FOR FUTURE PROJECTS DUE TO LACK OF NEGATIVE IMPACT ON THE COMMUNITY. FLOOD DATA REDRAWN FROM NOAA HISTORICAL FLOOD ARCHIVE