Scour-Critical Bridges in Iowa

Iowa has 395 bridges rated scour-critical by the Federal Highway Administration. These bridges have foundations that are unstable or at risk of undermining during flood events. Scour-critical doesn't mean a bridge is about to collapse — it means extra monitoring and countermeasures are in place — but these structures are priorities for repair or replacement.

How this ranking works

This state list filters to NBI scour ratings 0 through 3, then sorts by average daily traffic. It is intended to show flood-vulnerability exposure, not to label any bridge as currently unsafe.

Bridge	County	Scour Rating	Daily Traffic	Condition
US 67 over Miss Rvr Rr & Ia 461	Scott	3 — Serious	26,500	Poor
Ia 922-1st AVE over Cedar River	Linn	3 — Serious	13,000	Fair
SW 7th ST over Raccoon R & Trail	Polk	3 — Serious	7,253	Fair
Stone Pk BLVD over Perry Creek	Woodbury	3 — Serious	6,129	Fair
US 61 NB over Muscatine Slough	Muscatine	3 — Serious	3,500	Good
US 61 SB over Muscatine Slough	Muscatine	3 — Serious	3,500	Good
Country Club over Perry Creek	Woodbury	3 — Serious	1,675	Fair
FM - Olive over Nishnabotna River	Cass	3 — Serious	1,524	Poor
Ia 92 over Walnut Creek	Pottawattamie	3 — Serious	1,180	Fair
E53 237th ST over Raccoon River	Greene	3 — Serious	916	Fair
State ST over Drainage	Black Hawk	3 — Serious	783	Fair
FM over Little Rock River	Lyon	0 — Bridge closed	709	Poor
Main ST over Small Natural Stream	Winneshiek	3 — Serious	649	Poor
FM over Muddy Creek	Woodbury	3 — Serious	628	Poor
FM over Branch Beaver Creek	Grundy	3 — Serious	619	Poor
8th ST over Red Oak Creek	Montgomery	3 — Serious	571	Fair
FM over Brooks Creek	Buena Vista	3 — Serious	509	Poor
FM over Mud Creek	Lyon	3 — Serious	509	Poor
FM over Stream	Davis	3 — Serious	480	Poor
NE 38th ST over Drainage Ditch	Polk	3 — Serious	459	Poor
FM over Spring Creek	Benton	3 — Serious	430	Poor
FM over Weldon River	Decatur	3 — Serious	379	Poor
FM over Big Creek	Woodbury	3 — Serious	369	Poor
Tremont ST over Small Stream	Black Hawk	3 — Serious	342	Fair
FM - Highland over East Nishnabotna	Cass	3 — Serious	329	Fair
Clay ST over Drainage	Black Hawk	3 — Serious	320	Fair
FM over Klondike Creek	Lyon	3 — Serious	309	Poor
Main ST over East Boyer River	Crawford	3 — Serious	303	Poor
Local Road over Branch Otter Creek	Warren	3 — Serious	288	Poor
FM over Big Creek	Woodbury	3 — Serious	270	Poor
FM over Stream	Woodbury	3 — Serious	270	Poor
FM over W Fork Grand River	Ringgold	3 — Serious	219	Poor
Marquis RD over Shell Rock Riv Overflow	Black Hawk	3 — Serious	207	Poor
Marquis RD over Shell Rock Riv Overflow	Black Hawk	3 — Serious	207	Fair
FM over Little Cedar	Chickasaw	3 — Serious	196	Poor
FM over Drainage	Madison	3 — Serious	180	Poor
Local over Eagle Creek	Wright	3 — Serious	170	Fair
FM over Stream	Keokuk	3 — Serious	160	Poor
FM over Crane Creek	Chickasaw	3 — Serious	157	Poor
Local over Lamalees Creek	Lee	3 — Serious	150	Poor
Local over Sm Stream	Washington	3 — Serious	140	Fair
Lcl-jesup AVE over Major Drainage	Mills	0 — Bridge closed	133	Poor
FM over Nishnabotna River	Montgomery	3 — Serious	133	Fair
FM over Plum Creek	Ringgold	3 — Serious	120	Poor
FM over Upper Iowa River Branch	Winneshiek	3 — Serious	118	Fair
Local over Eagle Creek	Wright	3 — Serious	112	Fair
FM Tabor AVE over Small Stream	Harrison	2 — Critical	110	Poor
FM over Local Creek	Monroe	3 — Serious	110	Poor
Local over North Skunk River	Jasper	3 — Serious	106	Poor
Rosebud AVE over Buck Creek	Jasper	3 — Serious	104	Poor
S12th AVE E over Small Stream	Jasper	3 — Serious	104	Poor
S 24th AVE E over Small Stream	Jasper	3 — Serious	104	Poor
FM over Waterway	Madison	3 — Serious	100	Poor
550th AVE over Ballard Creek	Story	3 — Serious	100	Fair
W 36th ST S over Buck Creek	Jasper	3 — Serious	91	Poor
NE Rieck DR over Skunk River Tributary	Polk	3 — Serious	91	Fair
265th AVE over Creek	Lee	3 — Serious	90	Poor
Lcl-allis RD over Stream	Mills	3 — Serious	89	Poor
Local over Tarkio Creek	Montgomery	3 — Serious	89	Fair
FM over Sugar Creek	Cedar	3 — Serious	80	Fair
Local over Clear Creek	Cedar	3 — Serious	80	Fair
FM over Devil Creek	Lee	3 — Serious	80	Fair
FM over Drainage	Butler	3 — Serious	79	Fair
FM over West Fork Cedar River	Butler	3 — Serious	79	Poor
Local over Creek	Dubuque	3 — Serious	78	Poor
Local over Branch Beaver Creek	Grundy	3 — Serious	78	Fair
Local over Stream	Guthrie	3 — Serious	71	Fair
SE 124th ST over Camp Creek	Polk	3 — Serious	71	Fair
NW 146th AVE over Turkey Creek	Polk	3 — Serious	71	Fair
Ferris Mill RD over Creek	Winneshiek	3 — Serious	70	Poor
Local over Creek	Winneshiek	3 — Serious	70	Poor
Local over Small Stream	Winneshiek	3 — Serious	70	Fair
Local over Cold Water Creek	Winneshiek	3 — Serious	70	Fair
Local over Elkhorn Creek	Audubon	3 — Serious	62	Poor
Quail AVE over Otter CR	Franklin	3 — Serious	62	Fair
Local Road over Small Stream	Lyon	3 — Serious	62	Poor
Local Road over Pinney Creek	Lyon	3 — Serious	62	Poor
Local over Stream	Marion	3 — Serious	62	Poor
Local over Reeds CR	Van Buren	3 — Serious	62	Poor
Local Road over Minor Drainage	Montgomery	3 — Serious	61	Poor
E. 13th ST over Mud Ck	Benton	3 — Serious	60	Poor
Local over Brushy Fork Creek	Carroll	3 — Serious	60	Poor
FM over Small Stream	Iowa	3 — Serious	60	Poor
FM over Drainage	Madison	3 — Serious	60	Fair
Local over Avery Creek	Monroe	3 — Serious	60	Fair
FM over Nishnabotna	Montgomery	1 — Imminent failure	60	Poor
FM over Otter Creek	Osceola	3 — Serious	60	Fair
FM over Big Bear Creek	Poweshiek	3 — Serious	60	Poor
Local over Whiskey Creek	Washington	3 — Serious	60	Poor
Local over Muddy Creek	Woodbury	3 — Serious	60	Poor
Local over Stream	Woodbury	3 — Serious	60	Poor
Osage RD over Poyner Creek	Black Hawk	3 — Serious	59	Poor
180th ST over Quarter Section Run	Bremer	3 — Serious	59	Fair
Local over Hartgrave Ck	Butler	3 — Serious	59	Poor
FM Raven AVE over Baileye Creek	Franklin	3 — Serious	59	Fair
Coldwater Creek RD over Creek	Winneshiek	3 — Serious	59	Poor
Local over Miller Creek	Crawford	3 — Serious	58	Poor
Local RD over Nine Mile Creek	Adair	3 — Serious	51	Fair
Local over South Fork Iowa River	Hardin	3 — Serious	51	Poor
FM over Stream	Appanoose	3 — Serious	50	Poor
Local over Prairie Creek	Benton	3 — Serious	50	Poor
FM over Ioway Creek	Boone	3 — Serious	50	Poor
Local over Field Stream	Carroll	3 — Serious	50	Fair
Stone Mill RD over Rock Run Creek	Cedar	3 — Serious	50	Poor
Quincy AVE over Br Mill CR	Cedar	3 — Serious	50	Poor
Local over Branch Old Mans Creek	Iowa	3 — Serious	50	Poor
Local Road over Rat Creek	Lyon	3 — Serious	50	Fair
FM over Rat Creek	Lyon	3 — Serious	50	Fair
Local RD over N Br North River	Madison	3 — Serious	50	Poor
Lcl-merrill RD over Drainage	Mills	3 — Serious	50	Poor
Lcl-380th ST over Indian Creek	Mills	3 — Serious	50	Poor
Local over Creek	Van Buren	3 — Serious	50	Poor
FM over S Avery Creek	Wapello	3 — Serious	50	Fair
Local Road over South Fork Long Creek	Washington	3 — Serious	50	Fair
FM over Small Stream	Washington	3 — Serious	50	Poor
FM over Creek	Woodbury	3 — Serious	50	Poor
FM Spruce AVE over Maynes Creek	Franklin	3 — Serious	49	Poor
Local over Creek	Chickasaw	3 — Serious	47	Poor
Local over W Fk W Nishnabotna River	Crawford	3 — Serious	46	Poor
Local over Cedar Creek	Keokuk	3 — Serious	46	Poor
Local Road over Hefferman Creek	Lyon	3 — Serious	46	Poor
Local over Knack Creek	Webster	3 — Serious	46	Poor
Orange Avenue over East Nodaway River	Adams	3 — Serious	45	Fair
Filbert Avenue over Moore Creek	Adams	3 — Serious	45	Fair
Local (lwc) over Prairie Creek	Benton	3 — Serious	45	Fair
FM over Beaver Creek	Carroll	3 — Serious	45	Fair
S 64th AVE E over Sugar Creek	Jasper	3 — Serious	45	Poor
Local over Small Stream	Madison	3 — Serious	45	Fair
Fm-hutchings Av over Raines Branch	Mills	3 — Serious	45	Fair
Lcl-250th ST over Miller Creek	Mills	3 — Serious	45	Fair
Sycamore AVE over Stream	Page	3 — Serious	45	Poor
Emmett AVE over Deer Creek	Woodbury	3 — Serious	45	Poor
Ashley RD over Trib To Cedar River	Black Hawk	3 — Serious	44	Fair
Local over Branch Wolf Creek	Grundy	3 — Serious	44	Poor
Local Road over Creek	Winneshiek	3 — Serious	44	Fair
Local over Iowa River	Wright	3 — Serious	42	Poor
Local over Middle River	Adair	3 — Serious	41	Poor
Local - 665th over Jim Branch	Cass	3 — Serious	41	Poor
Local/buck Crk over Waterway	Cass	3 — Serious	41	Poor
Local over Buck Creek	Crawford	3 — Serious	41	Fair
310 Avenue over Brush Creek	Fremont	3 — Serious	41	Poor
Local Road over Klondike Creek	Lyon	3 — Serious	41	Poor
Local over Branch North Timber Crk	Marshall	3 — Serious	41	Poor
Lcl-ellington over Keg Creek	Mills	3 — Serious	41	Poor
Local Sec RD over Barry Creek	O'Brien	3 — Serious	41	Fair
Local 470th ST over Creek	Cherokee	3 — Serious	40	Poor
FM over Branch Otter Creek	Clarke	3 — Serious	40	Poor
FM over Middle Willow Creek	Crawford	3 — Serious	40	Fair
FM over Soldier River	Crawford	3 — Serious	40	Poor
FM over Troublesome Creek	Guthrie	3 — Serious	40	Poor
Local over Small	Lee	3 — Serious	40	Fair
Local over Moffat Branch	Monroe	3 — Serious	40	Fair
400th Street over Drainage	Pottawattamie	3 — Serious	40	Fair
Local over Stream	Ringgold	3 — Serious	40	Poor
Local over Stream	Ringgold	3 — Serious	40	Poor
Local over Salt Creek	Tama	3 — Serious	40	Fair
FM over Wolf Creek	Woodbury	3 — Serious	40	Poor
Local over Wild Cat Creek	Benton	3 — Serious	39	Poor
FM over Creek	Dubuque	3 — Serious	39	Poor
Local Road over Middle Fork Beaver Creek	Grundy	3 — Serious	39	Poor
FM over North Bear Creek	Winneshiek	3 — Serious	39	Poor
FM over Upper Iowa River	Winneshiek	3 — Serious	39	Poor
Local over Small Stream	Butler	3 — Serious	36	Fair
Local over Maynes Creek	Butler	3 — Serious	35	Fair
Local over W Br Wapsinonoc Creek	Cedar	3 — Serious	35	Poor
Local 40th ST over Beaver Creek	Franklin	3 — Serious	35	Poor
175th Street over Small Stream	Franklin	3 — Serious	35	Poor
Local over Small Stream	Jasper	3 — Serious	35	Poor
Local over Indian Creek	Jasper	3 — Serious	35	Poor
Local Road over Emery Creek	Lyon	3 — Serious	35	Poor
Local over Mud Creek	Benton	3 — Serious	34	Poor
Local over Br Stein Ck	Benton	3 — Serious	34	Poor
Grant AVE over Pioneer Creek	Cedar	3 — Serious	34	Poor
Local over East Soldier River	Crawford	3 — Serious	34	Poor
FM over S. Raccoon River	Guthrie	3 — Serious	34	Fair
Log AVE over West Rat Creek	Lyon	3 — Serious	34	Fair
170th ST over Drainage	Plymouth	3 — Serious	34	Poor
Local over Stream	Ringgold	3 — Serious	34	Poor
Local over Small Stream	Washington	3 — Serious	34	Fair
Local over Mcelhaney Creek	Woodbury	3 — Serious	34	Fair
Local over Little Sioux	Dickinson	3 — Serious	31	Poor
Local over Middle River	Adair	3 — Serious	30	Fair
110th Street over Middle Nodaway River	Adams	3 — Serious	30	Poor
FM over Walnut Creek	Appanoose	3 — Serious	30	Poor
Local over Small Stream	Butler	3 — Serious	30	Fair
Local over Small Stream	Butler	3 — Serious	30	Good
Local - 730th over Waterway	Cass	3 — Serious	30	Poor
Local over Rock Creek	Cedar	3 — Serious	30	Poor
Local over Little Wapsipinicon Rvr	Chickasaw	3 — Serious	30	Poor
380th ST over Prairie Ck	Clay	3 — Serious	30	Fair
Local over W Fk W Nishnabotna River	Crawford	3 — Serious	30	Poor
Local over Boyer River	Crawford	3 — Serious	30	Poor
Local over Big Creek	Crawford	3 — Serious	30	Poor
Local over East Soldier River	Crawford	3 — Serious	30	Fair
S 60th AVE W over Red Rock Creek	Jasper	3 — Serious	30	Poor
Local Road over Over Flow	Lyon	3 — Serious	30	Poor
Local over W Br Mill Creek	O'Brien	3 — Serious	30	Fair
Local over Silver Creek	Palo Alto	3 — Serious	30	Fair
Local over Big Whiskey Creek	Woodbury	3 — Serious	30	Poor
Local over Winnebago River	Worth	3 — Serious	30	Good