by democratandchronicle.com

United States Dam Safety Inspection

Map

Satisfactory

Fair

Poor

Unsatisfactory

Not Rated

Not Available

'Poor' or 'Unsatisfactory'
Condition

More than 50%

45-50%

40-45%

35-40%

30-35%

25-30%

20-25%

15-20%

10-15%

5-10%

Less than 5%

Less than 10 dams

United States Summary

Total Number of Dams: 91,262

Dam Condition	Total	High	Significant	Low	Undetermined	Not Available	Unknown
Number	Hazard Potential Classification
Total	91,262	10,385	14,479	54,847	4,262	7,244	45
Satisfactory	11,562	4,508	2,429	4,291	29	281	24
Fair	11,592	3,906	2,312	4,335	38	997	4
Poor	7,014	1,772	1,514	3,543	36	138	11
Unsatisfactory	852	251	116	387	3	95
Not Rated	54,886	2,123	3,237	39,704	4,085	5,731	6
Not Available	5,315	1,904	767	2,571	71	2
Unknown	41	15	10	16

Dam Condition	Total	High	Significant	Low	Undetermined	Not Available	Unknown
Percent	Hazard Potential Classification
Total	100%	11.4%	15.9%	60.1%	4.7%	7.9%	0.0%
Satisfactory	12.7%	4.9%	2.7%	4.7%	0.0%	0.3%	0.0%
Fair	12.7%	4.3%	2.5%	4.8%	0.0%	1.1%	0.0%
Poor	7.7%	1.9%	1.7%	3.9%	0.0%	0.2%	0.0%
Unsatisfactory	0.9%	0.3%	0.1%	0.4%	0.0%	0.1%
Not Rated	60.1%	2.3%	3.5%	43.5%	4.5%	6.3%	0.0%
Not Available	5.8%	2.1%	0.8%	2.8%	0.1%	0.0%
Unknown	0.0%	0.0%	0.0%	0.0%

State-by-state Dam Conditions

Area	Total	Number	Percent	Number	Percent	Number	Percent
		Condition Not Rated		'Poor' or 'Unsatisfactory' Condition
		Condition Not Rated		All hazard potential classification		'High' or 'Significant' hazard potential classification
Area	Total	#	%	#	%	#	%
United States	91,262	54,886	60.1%	7,866	8.6%	3,653	4.0%
Alabama	2,257	2,197	97.3%	0	0.0%	0	0.0%
Alaska	106	28	26.4%	11	10.4%	7	6.6%
Arizona	370	148	40.0%	25	6.8%	16	4.3%
Arkansas	1,259	1,197	95.1%	5	0.4%	1	0.1%
California	1,432	59	4.1%	20	1.4%	19	1.3%
Colorado	1,952	350	17.9%	135	6.9%	44	2.3%
Connecticut	780	201	25.8%	75	9.6%	71	9.1%
Delaware	83	23	27.7%	5	6.0%	4	4.8%
Florida	997	838	84.1%	22	2.2%	16	1.6%
Georgia	5,535	4,774	86.3%	214	3.9%	198	3.6%
Hawaii	129	0	0.0%	61	47.3%	57	44.2%
Idaho	397	8	2.0%	39	9.8%	17	4.3%
Illinois	1,636	5	0.3%	5	0.3%	1	0.1%
Indiana	1,088	179	16.5%	516	47.4%	272	25.0%
Iowa	4,053	3,692	91.1%	15	0.4%	7	0.2%
Kansas	6,450	5,813	90.1%	44	0.7%	38	0.6%
Kentucky	1,080	369	34.2%	221	20.5%	133	12.3%
Louisiana	682	58	8.5%	110	16.1%	11	1.6%
Maine	581	268	46.1%	61	10.5%	32	5.5%
Maryland	428	94	22.0%	85	19.9%	64	15.0%
Massachusetts	1,275	32	2.5%	300	23.5%	201	15.8%
Michigan	1,025	253	24.7%	84	8.2%	21	2.0%
Minnesota	1,170	307	26.2%	64	5.5%	8	0.7%
Mississippi	6,109	5,466	89.5%	234	3.8%	166	2.7%
Missouri	5,361	4,657	86.9%	17	0.3%	10	0.2%
Montana	2,983	2,633	88.3%	116	3.9%	22	0.7%
Nebraska	2,933	421	14.4%	693	23.6%	45	1.5%
Nevada	506	38	7.5%	156	30.8%	63	12.5%
New Hampshire	651	73	11.2%	151	23.2%	92	14.1%
New Jersey	829	105	12.7%	229	27.6%	176	21.2%
New Mexico	396	34	8.6%	190	48.0%	133	33.6%
New York	1,873	1,123	60.0%	274	14.6%	266	14.2%
North Carolina	3,484	899	25.8%	297	8.5%	221	6.3%
North Dakota	956	851	89.0%	33	3.5%	10	1.0%
Ohio	1,366	46	3.4%	514	37.6%	363	26.6%
Oklahoma	4,995	4,364	87.4%	52	1.0%	39	0.8%
Oregon	862	646	74.9%	38	4.4%	23	2.7%
Pennsylvania	1,488	213	14.3%	215	14.4%	179	12.0%
Rhode Island	234	74	31.6%	121	51.7%	67	28.6%
South Carolina	2,371	228	9.6%	1,158	48.8%	243	10.2%
South Dakota	2,569	2,476	96.4%	20	0.8%	10	0.4%
Tennessee	1,215	546	44.9%	16	1.3%	11	0.9%
Texas	7,377	5,739	77.8%	242	3.3%	2	0.0%
Utah	849	559	65.8%	14	1.6%	13	1.5%
Vermont	363	66	18.2%	99	27.3%	62	17.1%
Virginia	2,743	2,022	73.7%	72	2.6%	38	1.4%
Washington	805	270	33.5%	59	7.3%	51	6.3%
West Virginia	559	167	29.9%	42	7.5%	34	6.1%
Wisconsin	1,068	225	21.1%	61	5.7%	13	1.2%
Wyoming	1,515	52	3.4%	624	41.2%	51	3.4%
Guam	1	0	0.0%	0	0.0%	0	0.0%
Puerto Rico	36	0	0.0%	12	33.3%	12	33.3%

Data Dictionary

Condition Assessment

Satisfactory: No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair: No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor: A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory: A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated: The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available: Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High: Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant: Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low: Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined: Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available: Dams for which the downstream hazard potential is restricted to approved government users.

Source: National Inventory of Dams