Scour-Critical Bridges in South Dakota

South Dakota has 206 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
Sd079 over Meade St. Drainage	Pennington	3 — Serious	15,500	Good
I090 W over Ck	Minnehaha	3 — Serious	8,815	Fair
I090 E over Ck	Minnehaha	3 — Serious	8,815	Fair
I090 W over Lone Rock Ck	Minnehaha	3 — Serious	7,955	Fair
I090 E over Lone Rock Ck	Minnehaha	3 — Serious	7,955	Fair
Us083 over Bad Rv	Stanley	3 — Serious	6,040	Fair
Us016 W over Spring Ck	Pennington	3 — Serious	4,913	Fair
Us016 E over Spring Ck	Pennington	3 — Serious	4,913	Fair
Sd011 over Split Rock Ck	Minnehaha	3 — Serious	4,101	Fair
Sd038 over Skunk Ck	Minnehaha	3 — Serious	4,068	Fair
I090 W over Bull Ck	Pennington	3 — Serious	4,065	Fair
I090 E over Bull Ck	Pennington	3 — Serious	4,065	Fair
Us014 over James Rv	Beadle	3 — Serious	3,601	Poor
Sd011 over Nine Mile Ck	Lincoln	3 — Serious	3,042	Fair
Sd011 over Beaver Ck	Lincoln	3 — Serious	3,042	Fair
Us281 over Elm Rv	Brown	3 — Serious	3,041	Poor
387th Avenue over Cain Creek	Beadle	3 — Serious	2,600	Fair
Us014 B over Deer Ck	Brookings	3 — Serious	2,585	Fair
455th Avenue over Big Sioux River	Roberts	3 — Serious	2,500	Fair
Sd038 over James Rv	Davison	3 — Serious	2,445	Fair
Us014 over Ck	Kingsbury	3 — Serious	2,420	Fair
258th ST HWY 130 over Big Sioux River	Minnehaha	3 — Serious	2,419	Poor
Sd044 over West Fork Vermillion Rv	Turner	3 — Serious	2,416	Fair
44367 309th Street over James River	Yankton	2 — Critical	2,250	Fair
Us281 over Snake Ck	Spink	3 — Serious	2,141	Fair
Sd011 over Pipestone Ck	Minnehaha	3 — Serious	1,968	Fair
Us014 over South Medicine Ck	Hughes	3 — Serious	1,914	Fair
Sd028 over Lake Norden Outlet	Hamlin	3 — Serious	1,862	Fair
4th Avenue SW over Big Sioux River	Codington	3 — Serious	1,831	Fair
Sd038 over East Fork Vermillion Rv	McCook	3 — Serious	1,768	Fair
Sd079 over Belle Fourche Rv	Butte	3 — Serious	1,670	Fair
Sd044 over Pony Ck	Hutchinson	3 — Serious	1,657	Fair
Sd044 over Pony Ck	Hutchinson	3 — Serious	1,657	Fair
Sd044 over North Br Dry Ck	Hutchinson	3 — Serious	1,651	Fair
Sd044 over James Rv	Hutchinson	3 — Serious	1,651	Fair
Sd044 over Wolf Ck	Hutchinson	3 — Serious	1,651	Fair
Sd019 over East Fork Vermillion Rv	Turner	3 — Serious	1,648	Fair
Sd034 over Dry Run Ck	Hughes	3 — Serious	1,578	Fair
Us016a over Grace Coolidge Ck	Custer	3 — Serious	1,562	Fair
Us085 over Crow Ck	Butte	3 — Serious	1,543	Fair
Sd044 over Andes Ck	Douglas	3 — Serious	1,516	Fair
I-90 Service Road over Crow Ck	Lawrence	3 — Serious	1,500	Poor
455 Avenue over Ck	Codington	3 — Serious	1,425	Fair
478th AVE HWY 121 over Slip-up Creek	Minnehaha	3 — Serious	1,381	Fair
Sd028 over Big Sioux Rv	Hamlin	3 — Serious	1,371	Fair
Us085 over Buffalo Ck	Harding	3 — Serious	1,330	Fair
IRR Us018 over Slim Butte Ck	County 102	3 — Serious	1,294	Fair
Us281 over West Br Firesteel Ck	Aurora	3 — Serious	1,284	Fair
IRR Sd046 over Choteau Ck	Charles Mix	3 — Serious	1,199	Good
Us085 over Moreau Rv	Butte	3 — Serious	1,190	Fair
Us085 over Four Mile Ck	Butte	3 — Serious	1,190	Fair
Sd048 over East Union Ck	Union	3 — Serious	1,173	Fair
Sd048 over Drainage Ditch	Union	3 — Serious	1,173	Fair
455 Avenue over Mahoney Ck	Codington	3 — Serious	1,167	Poor
471st Avenue over Br North Deer Ck	Brookings	3 — Serious	1,163	Poor
IRR Us212 over Bear Ck	Ziebach	3 — Serious	1,130	Fair
Sd013 over Spring Ck	Moody	3 — Serious	1,073	Fair
Sd013 over Spring Ck	Moody	3 — Serious	1,073	Fair
Sd013 over Spring Ck	Moody	3 — Serious	1,073	Fair
466th Avenue over Long Creek	Lincoln	3 — Serious	1,017	Fair
466th Avenue over Long Creek	Lincoln	3 — Serious	1,017	Fair
Sd040 over Battle Ck	Pennington	3 — Serious	1,007	Fair
Sd040 over Battle Ck	Pennington	3 — Serious	1,007	Fair
Sd040 over Battle Ck	Pennington	3 — Serious	1,007	Fair
Sd044 over Vermillion Rv	Turner	3 — Serious	1,004	Fair
Sd037 over Antelope Ck	Brown	3 — Serious	993	Fair
Us014 over Cottonwood Ck	Jackson	3 — Serious	980	Fair
250th ST HWY 114 over Slip-up Creek	Minnehaha	3 — Serious	965	Poor
Sd045 over Br Smith Ck	Brule	3 — Serious	949	Fair
Sd045 over Crow Ck	Buffalo	3 — Serious	949	Fair
Sd022 over Hidewood Ck	Deuel	3 — Serious	932	Fair
Sd022 over Cobb Ck	Deuel	3 — Serious	932	Fair
Sd022 over Cobb Ck	Deuel	3 — Serious	932	Fair
IRR Sd047 over Soldier Ck	Buffalo	3 — Serious	917	Fair
Sd022 over Stray Horse Ck	Hamlin	3 — Serious	917	Fair
Sd037 over Crow Ck Ditch	Brown	3 — Serious	836	Fair
Sd011 over Drainage Ditch	Union	3 — Serious	776	Fair
Sd037 over Emanuel Ck	Bon Homme	3 — Serious	764	Fair
Sd045 over Crow Ck	Buffalo	3 — Serious	755	Fair
Sd262 over Wolf Ck	McCook	3 — Serious	749	Fair
204th Street over Big Sioux Rv	Brookings	3 — Serious	735	Fair
478th Avenue over Six Mile Ck	Brookings	3 — Serious	714	Fair
Sd034 over Chapelle Ck	Hughes	3 — Serious	691	Poor
Us212 over South Fork Snake Ck	Faulk	3 — Serious	688	Poor
235 ST over Park Ck	Lake	3 — Serious	684	Fair
Us385 over Horsehead Ck	Fall River	3 — Serious	673	Fair
455 Avenue over Ck	Codington	3 — Serious	672	Poor
Us018 over James Rv	Hutchinson	3 — Serious	668	Poor
Us014 over Mitchell Ck	Haakon	3 — Serious	650	Fair
Sd1804 over Okobojo Ck	Sully	3 — Serious	632	Fair
Us014 over Plum Ck	Stanley	3 — Serious	624	Fair
473rd Avenue over Big Slough Creek	Roberts	3 — Serious	620	Fair
471st Avenue over Trib. To Big Sioux River	Moody	3 — Serious	614	Fair
Us014 over Little Prairie Dog Ck	Stanley	3 — Serious	592	Good
IRR Sd063 over Dupree Ck	Ziebach	3 — Serious	590	Poor
Sd020 over North Fork Snake Ck	Faulk	3 — Serious	578	Fair
IRR Sd034 over Cheyenne Rv	Haakon	3 — Serious	567	Poor
29490 395th Avenue over Choteau Creek	Charles Mix	3 — Serious	564	Fair
200th ST over Redstone Ck	Kingsbury	3 — Serious	557	Fair
Sd050 over Pease Ck	Charles Mix	3 — Serious	553	Fair
31530 Universityrd over Vermillion Rv	Clay	3 — Serious	550	Good
Sd044 over West Br Bull Ck	Tripp	3 — Serious	540	Fair
Sd028 over Ck	Deuel	3 — Serious	502	Fair
410th Avenue over Firesteel Ck	Davison	3 — Serious	500	Fair
Nemo Rd. over Boxelder Ck	Meade	3 — Serious	500	Fair
5th Street over Split Rock Creek	Minnehaha	3 — Serious	500	Fair
Sd046 over Emanuel Ck	Bon Homme	3 — Serious	492	Fair
Sd042 over North Br Twelve Mile Ck	Hanson	3 — Serious	481	Fair
176 Street over Big Sioux Rv	Codington	3 — Serious	468	Poor
247th Street over James Rv	Davison	3 — Serious	466	Good
471st Street over North Deer Ck	Brookings	3 — Serious	462	Poor
250th Street over James Rv	Davison	3 — Serious	460	Fair
IRR Us012 over Hay Ck	Corson	3 — Serious	424	Fair
IRR Sd044 over Ck	Jackson	3 — Serious	420	Good
Sd011 over West Union Ck	Union	3 — Serious	406	Fair
Sd063 over Hermaphrodite Ck	Haakon	3 — Serious	405	Good
45390 280 ST over Ck	Turner	3 — Serious	403	Fair
IRR Us018 over Choteau Ck	Charles Mix	3 — Serious	387	Fair
264th Madison ST over Willow Ck	Minnehaha	3 — Serious	386	Fair
145 Street over Whetstone Rv	Grant	3 — Serious	374	Fair
Sd079 over Ck	Harding	3 — Serious	364	Good
Sd079 over North Fork Grand Rv	Harding	3 — Serious	364	Fair
486th Avenue over Spring Creek	Brookings	3 — Serious	361	Poor
Sd042 over Wolf Ck	McCook	3 — Serious	361	Fair
Sd079 over Moreau Rv	Harding	3 — Serious	356	Fair
IRR Sd127 over Big Slough Ck	Roberts	3 — Serious	354	Poor
Locust Street over Marne Creek	Yankton	3 — Serious	343	Fair
463 Avenue over Willow Ck	Codington	3 — Serious	340	Fair
248th ST HWY 110 over Big Sioux River	Minnehaha	3 — Serious	324	Fair
45460 272 ST over East Fork Vermillion Rv	Turner	3 — Serious	308	Fair
Sd044 over Black Pipe Ck	Mellette	3 — Serious	302	Fair
Sd026 over North Wolf Ck	Hand	3 — Serious	301	Fair
31160 Univer. Road over Vermillion Rv	Clay	3 — Serious	297	Fair
Sd019a over Ck	Turner	3 — Serious	293	Fair
Sd019a over Turkey Ridge Ck	Turner	3 — Serious	293	Fair
Main Street over Maple River	Brown	3 — Serious	267	Fair
41340 270 Str. over Coffee Ck	Hutchinson	3 — Serious	257	Fair
Sd248 over Medicine Ck	Jones	3 — Serious	251	Fair
291 Avenue over Okobojo Ck	Sully	3 — Serious	250	Fair
Sd020 over Ck	Grant	3 — Serious	244	Fair
183rd Street over Turtle Creek	Spink	3 — Serious	239	Fair
410th Avenue over Crow Creek Ditch	Brown	3 — Serious	234	Fair
214th Street over Cain Creek	Beadle	3 — Serious	233	Fair
New Underwood Rd. over West Elm Ck	Meade	3 — Serious	233	Good
208th ST over Ck	Kingsbury	3 — Serious	220	Poor
464 Avenue over Stray Horse Ck	Codington	3 — Serious	218	Fair
395th Avenue over Moccasin Creek	Brown	3 — Serious	214	Fair
394th Avenue over Creek	Beadle	3 — Serious	213	Poor
Fas 3214 over Dan Powell Ck	Stanley	3 — Serious	210	Poor
Fas 3214 over Bad Rv	Stanley	3 — Serious	210	Fair
Co RD 313 471st Av over Peg Munky Run Ck	Deuel	3 — Serious	200	Fair
45670 289 St. over Turkey Ridge Ck	Turner	3 — Serious	200	Fair
127th Street over Jorgenson River	Roberts	3 — Serious	198	Fair
472nd Avenue over N. Fork Whetstone Rv	Roberts	3 — Serious	195	Fair
259th Street over Split Rock Creek	Minnehaha	3 — Serious	194	Fair
354 Avenue over Ponca Ck	Gregory	3 — Serious	189	Poor
483 Avenue over Cobb Ck	Deuel	3 — Serious	179	Fair
483 Avenue over Cobb Ck	Deuel	3 — Serious	157	Fair
252nd Street over W. Fork Of Vermillion Rv	McCook	3 — Serious	157	Fair
374th Avenue over Sand Creek	Beadle	2 — Critical	156	Fair
Kenel Road over Oak Creek	Corson	3 — Serious	156	Fair
183 Avenue over North Fork Grand Rv	Perkins	3 — Serious	155	Fair
309th Avenue over Medicine Creek	Hughes	3 — Serious	152	Fair
252nd Street over Wolf Creek	McCook	3 — Serious	150	Fair
Snoma RD over Stinkingwater Ck	Butte	3 — Serious	149	Fair
148th ST over Mud Creek	Spink	3 — Serious	146	Fair
148th Streey over Creek	Spink	3 — Serious	146	Fair
152nd Street over N Fork Of Snake Creek	Faulk	3 — Serious	144	Fair
486 Avenue over Monighan Ck	Deuel	3 — Serious	143	Fair
Thunder Butte Road over Thunder Butte Ck	Ziebach	3 — Serious	143	Fair
Thunder Butte Road over Moreau Rv	Ziebach	3 — Serious	143	Fair
391st Avenue over Moccasin Creek	Brown	3 — Serious	141	Fair
Co RD 313 469th Av over Hidewood Ck	Deuel	3 — Serious	130	Fair
132nd Street over Creek	Walworth	3 — Serious	129	Fair
Buffalo Gap Road over Cheyenne Rv	Fall River	3 — Serious	128	Fair
Hidden Timber Road over Antelope Ck	Todd	3 — Serious	128	Poor
41109 292nd Street over Emanuel Creek	Bon Homme	3 — Serious	127	Fair
119th Street over Crow Creek Ditch	Brown	3 — Serious	125	Fair
27464 424 Ave. over Ck	Hutchinson	3 — Serious	125	Fair
486th Avenue over Flandreau Creek	Moody	3 — Serious	125	Fair
272 Street over Dog Ear Ck	Tripp	3 — Serious	110	Fair
392nd Avenue over Cain Creek	Beadle	3 — Serious	105	Poor
Fas 6247 over Bear Creek	Dewey	3 — Serious	103	Poor
243 ST over Ck	Aurora	3 — Serious	101	Fair
486 Avenue over Ck	Deuel	3 — Serious	89	Fair
Fas 3214 270 AVE over Lance Ck	Stanley	3 — Serious	85	Fair
303 Avenue over Sand Ck	Tripp	3 — Serious	71	Fair
125th Street over Jorgenson River	Roberts	3 — Serious	68	Fair
Vale Cutoff RD over Whitewood Ck	Butte	3 — Serious	65	Fair
482 Avenue over Whetstone Rv	Grant	3 — Serious	57	Poor
398th Avenue over Cain Creek	Beadle	3 — Serious	56	Fair
212th Street over Middle Pearl Creek	Beadle	2 — Critical	56	Poor
County Highway #23 over White Horse Ck	Mellette	3 — Serious	55	Fair
152 Street over Big Sioux Rv	Grant	3 — Serious	52	Fair
152 Street over Indian Rv	Grant	3 — Serious	52	Poor
257th Street over Split Rock Creek	Minnehaha	3 — Serious	52	Good
Us014 Ef over Prairie Dog Ck	Stanley	3 — Serious	50	Poor
Us014 Ef over Little Prairie Dog Ck	Stanley	3 — Serious	50	Poor
41790 246 St. over Rock Ck	Hanson	3 — Serious	35	Fair
County Highway #11 over Little White Rv	Mellette	3 — Serious	35	Fair