Rock River at Lake Koshkonong
Observed Fri, Sep 25, 1:00 PM CDT
- Flood stage
- 10.00 ft
- Record crest
- 15.13 ft2008
Flood stages and impacts
| Category | Stage |
|---|---|
| Major flood | 11.50 ft |
| Moderate flood | 11.00 ft |
| Minor flood | 10.00 ft |
| Action | 9.00 ft |
- 14.00 ftThere is widespread flooding of lakeside homes and roads in the Lake Koshkonong area including Vets Lane, Blackhawk Island Road and Oxbow Bend Road.
- 13.00 ftThere is widespread flooding of lakeside homes and roads in the Lake Koshkonong area including Vets Lane, Blackhawk Island Road and Oxbow Bend Road.
- 12.00 ftThere is widespread flooding of lakeside homes and roads in the Lake Koshkonong area including Vets Lane, Blackhawk Island Road and Oxbow Bend Road.
- 11.30 ftThere is knee-deep water over Blackhawk Island Road. Lamp Road on west side of river also becomes flooded. Lake Koshkonong merges with Mud Lake to the east of Lake Koshkonong.
- 11.00 ftIn the Town of Lake Koshkonong, floodwaters affect Vets Lane, Blackhawk Island Road, and Oxbow Bend Road. There is widespread flooding of roads and docks in the Town of Koshkonong and Town of Sumner including Vets Lane, Blackhawk Island Road and Oxbow Bend Road.
- 10.50 ftFloodwaters reach Oxbow Bend Road in the area of the gage on the east side of the lake. Flooded roads: The end of Road 9, end of E Road 8 St, end of E Road 7, Lakeview Dr, Charley Bluff Rd north of Royce Dallman Park, parts of Lamp Rd, Willow Rd, parts of Blackhawk Island Rd. Water surrounds some structures on Lamp Rd and towards end of Blackhawk Island Rd. Low lying areas of Lakeland Campground flood. Altpeter County Park floods. Water into yards along High Ridge Rd.
- 10.00 ftFloodwaters affect homes and boat docks in the Blackhawk Island area of Lake Koshkonong on the north side of the lake. Floodwaters spread over low spots on Blackhawk Island Road in the area where the Rock River enters the lake.
- 9.50 ftWater is into low lying areas along Lake Koshkonong. Water approaches homes along Blackhawk Island.
- 9.00 ftWater spreads into low lying areas along Lake Koshkonong. Water into yards along Blackhawk Island.
Flood outlook
Chance of flooding, September to November
| Category | Chance |
|---|---|
| Minor flooding | 19% |
| Moderate flooding | 6% |
| Major flooding | Under 5% |
The three-month chances are the River Forecast Centers’ long-range flood outlook, issued September 25, 2026.
Crest history
38 crests on NOAA’s list since 1990.
| # | Date | Stage |
|---|---|---|
| 1 | June 21, 2008 | 15.13 ft |
| 2 | April 22, 2013 | 12.35 ft |
| 3 | April 25, 1993 | 12.23 ft |
| 4 | April 18, 2008 | 11.65 ft |
| 5 | September 12, 2018 | 11.62 ft |
| 6 | March 25, 2019 | 11.50 ft |
| 7 | June 5, 2004 | 11.49 ft |
| 8 | April 24, 2026 | 11.42 ft |
| 9 | March 29, 2009 | 11.37 ft |
| 10 | July 31, 2010 | 11.17 ft |
| 11 | October 15, 2018 | 11.07 ft |
| 12 | June 7, 2000 | 11.02 ft |
| 13 | October 15, 2019 | 11.02 ft |
| 14 | October 15, 2019 | 10.95 ft |
| 15 | April 7, 2007 | 10.58 ft |
| 16 | August 30, 2007 | 10.46 ft |
| 17 | May 20, 2018 | 10.33 ft |
| 18 | July 7, 2024 | 10.10 ft |
| 19 | March 30, 2011 | 10.09 ft |
| 20 | June 30, 2013 | 10.02 ft |
| 21 | May 2, 2009 | 10.02 ft |
| 22 | June 13, 2024 | 10.01 ft |
| 23 | May 6, 2017 | 9.78 ft |
| 24 | April 23, 1998 | 9.77 ft |
| 25 | April 28, 1999 | 9.73 ft |
Most recent crests
- April 24, 2026: 11.42 ft
- July 7, 2024: 10.10 ft
- June 13, 2024: 10.01 ft
- October 15, 2019: 11.02 ft
- October 15, 2019: 10.95 ft
- March 25, 2019: 11.50 ft
- October 15, 2018: 11.07 ft
- September 12, 2018: 11.62 ft
- May 20, 2018: 10.33 ft
- May 6, 2017: 9.78 ft
Nearby
Upstream, downstream and the gauges around this one.
What this means
Forecasts by the North Central River Forecast Center. Forecasts are issued as needed during times of high water, but are not routinely available. River forecasts for this location take into account past precipitation and the precipitation amounts expected approximately 24 hours into the future from the forecast issuance time. River forecasts for this location take into account past precipitation and the precipitation amounts expected approximately 48 hours into the future from the forecast issuance time.
Sources
Stage, flood stages, impacts and crest history from NOAA’s National Water Prediction Service. Streamflow and the daily record from the U.S. Geological Survey.