Dam Name
Official name of the dam. No abbreviations used unless a part of the official name. For dams that do not have an official name, the popular name is used.
Other Names
Reservoir name or names in common use other than the official name of the dam. Names are separated with semi-colons.
Dam Former Name
Any previous reservoir or dam name(s), if changed. Names are separated with semi-colons.
State or Federal Agency ID
Official State or Agency identification number for the dam.
NID ID
The official NID identification number for the dam, known formerly as the National ID.
This field is used as the unique identifier for each dam record.
The first two characters of the identity are the state two-letter abbreviation, based on the location of the dam.
The last five characters of the identity are a unique number (AB#####).
The NID ID is the Corps Identification Number assigned to each dam in the 1995-96 NID update, under the National Dam Inspection Program (P.L. 92-367).
Once assigned, this number should not change. The following guidelines are provided for assignment of ID numbers for new dams.
Each new dam will be assigned an NID ID number by the state or federal coordinator. NID ID numbers will not be reused.
If a dam is retired or no longer in existence, that ID number is retired. The state coordinator is responsible for assigning ID numbers for
all dams, regardless of ownership. The numbers may not necessarily be continuous, because of a previously established scheme which assigned
certain number ranges to federal agencies. Continued use of this numbering scheme for new dams is at the discretion of the state coordinator.
Please contact ASDSO or USACE Dam Safety Team for further information on the process of assigning NID ID numbers.
Longitude
Longitude at dam centerline as a single value in decimal degrees.
Latitude
Latitude at dam centerline as a single value in decimal degrees.
Section, Township, Range Location
Dam location in terms of Section, Township, and Range. Meridian location is included if it is needed to locate the dam.
County
Name of the county in which the dam is located.
River or Stream
Official name of the river or stream on which the dam is built. If the stream is unnamed, it is identified as a tributary ("TR") to the named river. If the dam is located offstream, the name of the river or stream is entered plus "-OS" or "OFFSTREAM".
State
The two letter abbreviation for the state in which the dam is located. A calculated field based on the field item #6 NIDID.
Nearest City/Town
Name of the nearest city, town, or village that is most likely to be affected by floods resulting from the failure of the dam.
Distance to Nearest City/Town
Distance from the dam to the nearest affected City/Town/Village, to the nearest mile (and tenth if appropriate).
Owner Name
Name of the owner of the dam.
Owner Type
Code indicating owner type:
F for Federal
S for State
L for Local Government
U for Public Utility
P for Private
Dam Designer
Name of the principal firm(s) or agency accomplishing design of dam and major appurtenant operating features, and major modifications. The original designer is listed first then modification designers (if applicable). The names are separated with semi-colons.
Private Dam On Federal Property
Code indicating whether the dam is a private dam located on federal property:
Y for Yes
N for No
Dam Type
Code indicating the type of dam (in order of importance):
RE for Earth
ER for Rockfill
PG for Gravity
CB for Buttress
VA for Arch
MV for Multi-Arch
CN for Concrete
MS for Masonry
ST for Stone
TC for Timber Crib
OT for Other
Codes are concatenated if the dam is a combination of several types. For example, the entry CNCB would indicate a concrete buttress dam type.
Core
Code indicating the position, type of watertight member and certainty.
Position:
F for upstream facing
H for homogeneous dam
I for core
X for unlisted/unknown
Type: A for bituminous concrete
C for concrete
E for earth
M for metal
P for plastic
X for unlisted/unknown
Certainty
K for known
Z for estimated
Foundation
Code for the material upon which dam is founded, and certainty.
Foundation:
R for rock
RS for rock and soil
S for soil
U for unlisted/unknown
Certainty:
K for known
Z for estimated
Purposes
Codes indicating the purposes for which the reservoir is used:
I for Irrigation
H for Hydroelectric
C for Flood Control and Storm Water Management
N for Navigation
S for Water Supply
R for Recreation
P for Fire Protection, Stock, or Small Farm Pond
F for Fish and Wildlife Pond
D for Debris Control
T for Tailings
O for Other
The order indicates the relative decreasing importance of the purpose. Codes are concatenated if the dam has multiple purposes. For example, SCR would indicate the primary purposes, Water Supply and Flood Control and Storm Water Management, followed by Recreation.
Year Completed
Year when the original main dam structure was completed, optionally followed by code ("E") to indicate an estimated date. If unknown, and reasonable estimate is unavailable, "0000" will be used.
Year Modified
Year (four digit) when major modifications or rehabilitation of dam or major control structures were completed. Major modifications are defined as a structural, foundation, or mechanical construction activity which significantly restores the project to original condition; changes the project’s operation; capacity or structural characteristics (e.g. spillway or seismic modification); or increases the longevity, stability, or safety of the dam and appurtenant structures.
Modification Type
S for structural
F for foundation
M for mechanical
E for seismic
H for hydraulic
O for other
Modifications are separated by semicolons.
Dam Length
Length of the dam, in feet, which is defined as the length along the top of the dam. This length also includes the spillway, powerplant, navigation lock, fish pass, etc., where these form part of the length of the dam. If detached from the dam, these structures should not be included.
DAM HEIGHT: Because the "height of dam" definition used by each of the participating
State and Federal agencies varies, three different height fields are provided in the NID database. Each agency is requested to enter values for
the height field item(s) that most closely correspond to the height of the dam definition(s) used by the agency. Height field items that do not
correspond to agency data may be left blank.
Dam Height
Height of the dam, in feet to the nearest foot, which is defined as the vertical distance between the lowest point on the crest of the dam and the lowest point in the original streambed.
Structural Height
Structural height of the dam, in feet to the nearest foot, which is defined as the vertical distance from the lowest point of the excavated foundation to the top of the dam.
Hydraulic Height
Hydraulic height of the dam, in feet to the nearest foot, which is defined as the vertical difference between the maximum design water level and the lowest point in the original streambed.
Maximum Discharge
Number of cubic feet per second (cu ft/sec) which the spillway is capable of discharging when the reservoir is at its maximum designed water surface elevation.
Maximum Storage
Maximum storage, in acre-feet, which is defined as the total storage space in a reservoir below the maximum attainable water surface elevation, including any surcharge storage.
Normal Storage
Normal storage, in acre-feet, which is defined as the total storage space in a reservoir below the normal retention level, including dead and inactive storage and excluding any flood control or surcharge storage.
Surface Area
Surface area, in acres, of the impoundment at its normal retention level.
Drainage Area
Drainage area of the dam, in square miles, which is defined as the area that drains to a particular point (in this case, the dam) on a river or stream.
| Downstream Hazard Potential | |||||||||||||
| Code indicating the potential hazard to the downstream area resulting from failure or misoperation of the dam or facilities: | |||||||||||||
| L for Low | |||||||||||||
| S for Significant | |||||||||||||
| H for High | |||||||||||||
| Definitions, as accepted by the Interagency Committee on Dam Safety, are as follows: | |||||||||||||
| LOW HAZARD POTENTIAL: Dams assigned the low hazard potential classification are those where failure or misoperation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner’s property. | |||||||||||||
| SIGNIFICANT HAZARD POTENTIAL: Dams assigned the significant hazard potential classification are those dams where failure or misoperation 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 located in areas with population and significant infrastructure. | |||||||||||||
| HIGH HAZARD POTENTIAL: Dams assigned the high hazard potential classification are those where failure or misoperation will probably cause loss of human life. | |||||||||||||
| |||||||||||||
Emergency Action Plan
Code, indicating whether the dam has an Emergency Action Plan (EAP) developed by the dam owner.
An EAP is defined as a plan of action to be taken to reduce the potential for property damage and loss of life in an area affected by a
dam failure or large flood.
Y for Yes
N for No
NR for Not Required by submitting agency.
Inspection Date
Date of the most recent inspection of the dam prior to the transmittal of the data by the submitting agency.
Inspection Frequency
Scheduled frequency interval for periodic inspections, in years.
State Regulated Dam
Code indicating whether the dam is "State Regulated" under the National Dam Safety Program Act:
Y for Yes
N for No
A "State Regulated Dam" is defined as a dam meeting the NID criteria for which the State executes one or more of the following general responsibilities: (a) Inspection; (b) Enforcement; or (c) Permitting.
State Regulatory Agency
Name of the primary state agency with regulatory or approval authority over the dam.
Spillway Types
Code that describes the type of spillway:
C for Controlled
U for Uncontrolled
N for None.
Spillway Width
Width of the spillway, to the nearest foot, available for discharge when the reservoir is at its maximum designed water surface elevation.
Outlet Gates
Code(s) that describe the type of spillway and controlled outlet gates, if any:
X for None
U for Uncontrolled
T for Tainter (radial)
L for Vertical Lift
R for Roller
B for Bascule
D for Drum
N for Needle
F for Flap
S for Slide (sluice gate)
V for Valve
O for Other controlled
Types are entered in decreasing size order, separated by semicolons, followed by number of gates.
Volume of Dam
Number of existing navigation locks for the project.
Number of Locks
Total number of cubic yards occupied by the materials used in the dam structure. Portions of powerhouse, locks, and spillways are included only if they are an integral part of the dam and required for structural stability.
Length of Locks
Length of the primary navigation lock to the nearest foot.
Lock Width
Width of the primary navigation lock to the nearest foot.
Length of Locks
Length of the primary navigation lock to the nearest foot.
Lock Width
Width of the primary navigation lock to the nearest foot.
Federal Agency Involvement in Funding
Code identifying which federal agency was involved in funding of the dam. Codes are concatenated if several agencies were involved.
Federal Agency Involvement in Design
Code identifying which federal agency was involved in the design of the dam. Codes are concatenated if several agencies were involved.
Federal Agency Involvement in Construction
Code identifying which federal agency was involved in the construction of the dam. Codes are concatenated if several agencies were involved.
Federal Agency Involvement in Regulatory
Code identifying which federal agency is involved in the regulation of the dam. Codes are concatenated if several agencies are involved.
Federal Agency Involvement in Inspection
Code identifying which federal agency is involved in the inspection of the dam. Codes are concatenated if several agencies are involved.
Federal Agency Involvement in Operation
Code identifying which federal agency is involved in the operation of the dam. Codes are concatenated if several agencies are involved.
Federal Agency Owner
Code identifying which federal agency partly or wholly owns the dam. Codes are concatenated if several owners are involved.
Federal Agency Involvement in Other
Code identifying which federal agency is involved in other aspects of the dam. Codes are concatenated if several owners are involved.
Source Agency
Code identifying the federal or state source agency that has provided the field data on the dam. The code used for a state source agency is the two letter abbreviation for the state; the code used for a federal source agency is the Federal Agency Code defined in the table below.