National Dam Safety Program. Crab Orchard Creek Dam (Inventory Number VA 02102), New River Basin, Bland County, Virginia. Phase I Inspection Report

Download National Dam Safety Program. Crab Orchard Creek Dam (Inventory Number VA 02102), New River Basin, Bland County, Virginia. Phase I Inspection Report PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 44 pages
Book Rating : 4.:/5 (227 download)

DOWNLOAD NOW!


Book Synopsis National Dam Safety Program. Crab Orchard Creek Dam (Inventory Number VA 02102), New River Basin, Bland County, Virginia. Phase I Inspection Report by : James A. Walsh

Download or read book National Dam Safety Program. Crab Orchard Creek Dam (Inventory Number VA 02102), New River Basin, Bland County, Virginia. Phase I Inspection Report written by James A. Walsh and published by . This book was released on 1980 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of a Phase I investigation is to identify expeditiously those dams which may pose hazards to human life or property. The assessment of the general conditions of the dam is based upon available data and visual inspections. Detailed investigation and analyses involving topographic mapping, subsurface investigations, testing, and detailed computational evaluations are beyond the scope of a Phase I investigation; however, the investigation is intended to identify any need for such studies. Based upon the field conditions at the time of the field inspection and all available engineering data, the Phase I report addresses the hydraulic, hydrologic, geologic, geotechnic, and structural aspects of the dam. The engineering techniques employed give a reasonably accurate assessment of the conditions of the dam. It should be realized that certain engineering aspects cannot be fully analyzed during a Phase I inspection. Assessment and remedial measures in the report include the requirements of additional indepth study when necessary. Phase I reports include project information of the dam and appurtenances, all existing engineering data, operational procedures, hydraulic/hydrologic data of the watershed, dam stability, visual inspection report and an assessment including required remedial measures.

Technical Abstract Bulletin

Download Technical Abstract Bulletin PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 228 pages
Book Rating : 4.E/5 ( download)

DOWNLOAD NOW!


Book Synopsis Technical Abstract Bulletin by :

Download or read book Technical Abstract Bulletin written by and published by . This book was released on 1981 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Government Reports Announcements & Index

Download Government Reports Announcements & Index PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 1176 pages
Book Rating : 4.:/5 (319 download)

DOWNLOAD NOW!


Book Synopsis Government Reports Announcements & Index by :

Download or read book Government Reports Announcements & Index written by and published by . This book was released on 1981 with total page 1176 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Government Reports Annual Index

Download Government Reports Annual Index PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 932 pages
Book Rating : 4.3/5 (91 download)

DOWNLOAD NOW!


Book Synopsis Government Reports Annual Index by :

Download or read book Government Reports Annual Index written by and published by . This book was released on 1981 with total page 932 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.

National Dam Safety Program. Robertson Dam (Inventory Number VA 16303), James River Basin, Rockbridge County, State of Virginia. Phase I Inspection Report

Download National Dam Safety Program. Robertson Dam (Inventory Number VA 16303), James River Basin, Rockbridge County, State of Virginia. Phase I Inspection Report PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 70 pages
Book Rating : 4.:/5 (227 download)

DOWNLOAD NOW!


Book Synopsis National Dam Safety Program. Robertson Dam (Inventory Number VA 16303), James River Basin, Rockbridge County, State of Virginia. Phase I Inspection Report by : James A. Walsh

Download or read book National Dam Safety Program. Robertson Dam (Inventory Number VA 16303), James River Basin, Rockbridge County, State of Virginia. Phase I Inspection Report written by James A. Walsh and published by . This book was released on 1979 with total page 70 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pursuant to Public Law 92-367, Phase I Inspection Reports are prepared under guidance contained in the recommended guidelines for safety inspection of dams, published by the Office of Chief of Engineers, Washington, D.C. 20314. The purpose of a Phase I investigation is to identify expeditiously those dams which may pose hazards to human life or property. The assessment of the general conditions of the dam is based upon available data and visual inspections. Detailed investigation and analyses involving topographic mapping, subsurface investigations, testing, and detailed computational evaluations are beyond the scope of a Phase I investigation; however, the investigation is intended to identify any need for such studies. Based upon the field conditions at the time of the field inspection and all available engineering data, the Phase I report addresses the hydraulic, hydrologic, geologic, geotechnic, and structural aspects of the dam. The engineering techniques employed give a reasonably accurate assessment of the conditions of the dam. It should be realized that certain engineering aspects cannot be fully analyzed during a Phase I inspection. Assessment and remedial measures in the report include the requirements of additional indepth study when necessary.

National Dam Safety Program. Roanoke Number 72A Inventory Number VA-03702. Roanoke River Basin, Charlotte County, State of Virginia. Phase I Inspection Report

Download National Dam Safety Program. Roanoke Number 72A Inventory Number VA-03702. Roanoke River Basin, Charlotte County, State of Virginia. Phase I Inspection Report PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 91 pages
Book Rating : 4.:/5 (227 download)

DOWNLOAD NOW!


Book Synopsis National Dam Safety Program. Roanoke Number 72A Inventory Number VA-03702. Roanoke River Basin, Charlotte County, State of Virginia. Phase I Inspection Report by : Roland B. Phillips

Download or read book National Dam Safety Program. Roanoke Number 72A Inventory Number VA-03702. Roanoke River Basin, Charlotte County, State of Virginia. Phase I Inspection Report written by Roland B. Phillips and published by . This book was released on 1979 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: Roanoke Creek No. 72A is a zoned, earthfill dam approximately 650 feet long and 46 feet high. The dam, located on Twittys Creek approximately 2 miles east of the Town of Drakes Branch, Virginia, is used for flood control. Roanoke No. 72A dam is an 'intermediate' 'size-high' hazard structure as defined by the Recommended Guidelines for Safety Inspection of Dams. Visual inspection and office analyses indicate no deficiencies requiring emergency attention.

National Dam Safety Program. Swift Creek Reservoir Dam (Inventory Number VA-04112), Middle James River Basin, Chesterfield County, Virginia. Phase I Inspection Report

Download National Dam Safety Program. Swift Creek Reservoir Dam (Inventory Number VA-04112), Middle James River Basin, Chesterfield County, Virginia. Phase I Inspection Report PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 104 pages
Book Rating : 4.:/5 (227 download)

DOWNLOAD NOW!


Book Synopsis National Dam Safety Program. Swift Creek Reservoir Dam (Inventory Number VA-04112), Middle James River Basin, Chesterfield County, Virginia. Phase I Inspection Report by : Paul Seiler

Download or read book National Dam Safety Program. Swift Creek Reservoir Dam (Inventory Number VA-04112), Middle James River Basin, Chesterfield County, Virginia. Phase I Inspection Report written by Paul Seiler and published by . This book was released on 1979 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pursuant to Public Law 92-367, Phase I Inspection Reports are prepared under guidance contained in the recommended guidelines for safety inspection of dams, published by the Office of Chief of Engineers, Washington, D.C. 20314. The purpose of a Phase I investigation is to identify expeditiously those dams which may pose hazards to human life or property. The assessment of the general conditions of the dam is based upon available data and visual inspections. Detailed investigation and analyses involving topographic mapping, subsurface investigations, testing, and detailed computational evaluations are beyond the scope of a Phase I investigation; however, the investigation is intended to identify any need for such studies. Based upon the field conditions at the time of the field inspection and all available engineering data, the Phase I report addresses the hydraulic, hydrologic, geologic, geotechnic, and structural aspects of the dam. The engineering techniques employed give a reasonably accurate assessment of the conditions of the dam. It should be realized that certain engineering aspects cannot be fully analyzed during a Phase I inspection. Assessment and remedial measures in the report include the requirements of additional indepth study when necessary.

National Dam Safety Program. Orchard Dam (Inventory Number VA 16103) Staunton River Basin. Roanoke County, Virginia. Phase I Inspection Report

Download National Dam Safety Program. Orchard Dam (Inventory Number VA 16103) Staunton River Basin. Roanoke County, Virginia. Phase I Inspection Report PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 40 pages
Book Rating : 4.:/5 (227 download)

DOWNLOAD NOW!


Book Synopsis National Dam Safety Program. Orchard Dam (Inventory Number VA 16103) Staunton River Basin. Roanoke County, Virginia. Phase I Inspection Report by : Boris O. Taran

Download or read book National Dam Safety Program. Orchard Dam (Inventory Number VA 16103) Staunton River Basin. Roanoke County, Virginia. Phase I Inspection Report written by Boris O. Taran and published by . This book was released on 1981 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Orchard dam is an earthfill structure approximately 1050 feet long and 27.5 feet high. The visual inspection revealed one item that should be taken care of before refilling the reservoir. Maintenance is performed by the owner. However, there is no regular maintenance operation program or emergency operations and warning plan. It is recommended that a regular maintenance and operations program be instituted with provisions for accurate records of all maintenance performed. It is also recommened that a warning system be established and that the maintenance items listed in Section 7.2 be accomplished as a part of the regular maintenance program within the next 12 months.

National Dam Safety Program. Johns Creek Number 2 (Inventory Number VA 04501), James River Basin, Craig County, State of Virginia. Phase I Inspection Report

Download National Dam Safety Program. Johns Creek Number 2 (Inventory Number VA 04501), James River Basin, Craig County, State of Virginia. Phase I Inspection Report PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 102 pages
Book Rating : 4.:/5 (227 download)

DOWNLOAD NOW!


Book Synopsis National Dam Safety Program. Johns Creek Number 2 (Inventory Number VA 04501), James River Basin, Craig County, State of Virginia. Phase I Inspection Report by : James A. Walsh

Download or read book National Dam Safety Program. Johns Creek Number 2 (Inventory Number VA 04501), James River Basin, Craig County, State of Virginia. Phase I Inspection Report written by James A. Walsh and published by . This book was released on 1979 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Johns Creek No. 2 Dam is a zoned, earthfill dam approximately 650 feet long and 51 feet high. The dam, located approximately 18 miles southwest of New Castle, Virginia is used for flood control. Johns Creek No. 2 Dam is an 'intermediate' size - 'significant' hazard structure as defined by the Recommended Guidelines for Safety Inspection of Dams. Using the Corps of Engineers' screening criteria for initial review of spillway adequacy, the 1/2 Probable Maximum Flood (1/2 PMF) was selected as the spillway design flood (SDF). The SDF was routed through the reservoir and found to overtop the dam by a maximum depth of 2.1 feet with an average critical velocity of 3.8 f.p.s. Total duration of dam overtopping would be approximately 3.2 hours. The dam and appurtenant structures were found to be in generally good overall condition. No conditions indicating embankment instability were detected during the field inspection and office analyses. Seepage at the toe of the dam is not considered serious; however, it is recommended that the rate be checked for increase at higher reservoir levels. The safety factors determined during design are greater than those required for minimum accepted stability.

Phase I Inspection Report, National Dam Safety Program

Download Phase I Inspection Report, National Dam Safety Program PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 84 pages
Book Rating : 4.:/5 (359 download)

DOWNLOAD NOW!


Book Synopsis Phase I Inspection Report, National Dam Safety Program by : United States. Army. Corps of Engineers. Norfolk District

Download or read book Phase I Inspection Report, National Dam Safety Program written by United States. Army. Corps of Engineers. Norfolk District and published by . This book was released on 1978 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Bahnhofs- und Ortsverzeichnis für den Gepäck- und Expreßgutverkehr

Download Bahnhofs- und Ortsverzeichnis für den Gepäck- und Expreßgutverkehr PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 72 pages
Book Rating : 4.:/5 (698 download)

DOWNLOAD NOW!


Book Synopsis Bahnhofs- und Ortsverzeichnis für den Gepäck- und Expreßgutverkehr by :

Download or read book Bahnhofs- und Ortsverzeichnis für den Gepäck- und Expreßgutverkehr written by and published by . This book was released on 1983 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:

National Dam Safety Program. Mays Dam (Inventory Number VA 00909), James River Basin, Amherst County, State of Virginia. Phase I Inspection Report

Download National Dam Safety Program. Mays Dam (Inventory Number VA 00909), James River Basin, Amherst County, State of Virginia. Phase I Inspection Report PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 51 pages
Book Rating : 4.:/5 (227 download)

DOWNLOAD NOW!


Book Synopsis National Dam Safety Program. Mays Dam (Inventory Number VA 00909), James River Basin, Amherst County, State of Virginia. Phase I Inspection Report by : James A. Walsh

Download or read book National Dam Safety Program. Mays Dam (Inventory Number VA 00909), James River Basin, Amherst County, State of Virginia. Phase I Inspection Report written by James A. Walsh and published by . This book was released on 1979 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pursuant to Public Law 92-367, Phase I Inspection Reports are prepared under guidance contained in the recommended guidelines for safety inspection of dams, published by the Office of Chief of Engineers, Washington, D.C. 20314. The purpose of a Phase I investigation is to identify expeditiously those dams which may pose hazards to human life or property. The assessment of the general conditions of the dam is based upon available data and visual inspections. Detailed investigation and analyses involving topographic mapping, subsurface investigations, testing, and detailed computational evaluations are beyond the scope of a Phase I investigation; however, the investigation is intended to identify any need for such studies. Based upon the field conditions at the time of the field inspection and all available engineering data, the Phase I report addresses the hydraulic, hydrologic, geologic, geotechnic, and structural aspects of the dam. The engineering techniques employed give a reasonably accurate assessment of the conditions of the dam. It should be realized that certain engineering aspects cannot be fully analyzed during a Phase I inspection. Assessment and remedial measures in the report include the requirements of additional indepth study when necessary.

National Dam Safety Program. Timber Lake Dam. (Inventory Number VA 03102), Roanoke River Basin, Campbell County, Virginia. Phase I Inspection Report

Download National Dam Safety Program. Timber Lake Dam. (Inventory Number VA 03102), Roanoke River Basin, Campbell County, Virginia. Phase I Inspection Report PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 51 pages
Book Rating : 4.:/5 (227 download)

DOWNLOAD NOW!


Book Synopsis National Dam Safety Program. Timber Lake Dam. (Inventory Number VA 03102), Roanoke River Basin, Campbell County, Virginia. Phase I Inspection Report by : Ray E. Martin

Download or read book National Dam Safety Program. Timber Lake Dam. (Inventory Number VA 03102), Roanoke River Basin, Campbell County, Virginia. Phase I Inspection Report written by Ray E. Martin and published by . This book was released on 1980 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pursuant to Public Law 92-367, Phase I Inspection Reports are prepared under guidance contained in the Recommended Guidelines for Safety Inspection of Dams, published by the Office of Chief of Engineers, Washington, D.C. 20314. The purpose of a Phase I investigation is to identify expeditiously those dams which may pose hazards to human life or property. The assessment of the general conditions of the dam is based upon available data and visual inspections. Detailed investigation and analyses involving topographic mapping, subsurface investigations, testing, and detailed computational evaluations are beyond the scope of a Phase I investigation; however, the investigation is intended to identify any need for such studies. Based upon the field conditions at the time of the field inspection and all available engineering data, the Phase I report addresses the hydraulic, hydrologic, geologic, geotechnic, and structural aspects of the dam. The engineering techniques employed give a reasonably accurate assessment of the conditions of the dam. It should be realized that certain engineering aspects cannot be fully analyzed during a Phase I inspection. Assessment and remedial measures in the report include the requirements of additional indepth study when necessary. Phase I reports include project information of the dam and appurtenances, all existing engineering data, operational procedures, hydraulic/hydrologic data of the watershed, dam stability, visual inspection report and an assessment including required remedial measures. (Author).

National Dam Safety Program. Hunting Camp Dam (Inventory Number VA 02101), Bland County, Virginia. Phase I Inspection Report

Download National Dam Safety Program. Hunting Camp Dam (Inventory Number VA 02101), Bland County, Virginia. Phase I Inspection Report PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 64 pages
Book Rating : 4.:/5 (227 download)

DOWNLOAD NOW!


Book Synopsis National Dam Safety Program. Hunting Camp Dam (Inventory Number VA 02101), Bland County, Virginia. Phase I Inspection Report by : James A. Walsh

Download or read book National Dam Safety Program. Hunting Camp Dam (Inventory Number VA 02101), Bland County, Virginia. Phase I Inspection Report written by James A. Walsh and published by . This book was released on 1979 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pursuant to Public Law 92-367, Phase I Inspection Reports are prepared under guidance contained in the recommended guidelines for safety inspection of dams, published by the Office of Chief of Engineers, Washington, D.C. 20314. The purpose of a Phase I investigation is to identify expeditiously those dams which may pose hazards to human life or property. The assessment of the general conditions of the dam is based upon available data and visual inspections. Detailed investigation and analyses involving topographic mapping, subsurface investigations, testing, and detailed computational evaluations are beyond the scope of a Phase I investigation; however, the investigation is intended to identify any need for such studies. Based upon the field conditions at the time of the field inspection and all available engineering data, the Phase I report addresses the hydraulic, hydrologic, geologic, geotechnic, and structural aspects of the dam. The engineering techniques employed give a reasonably accurate assessment of the conditions of the dam. It should be realized that certain engineering aspects cannot be fully analyzed during a Phase I inspection. Assessment and remedial measures in the report include the requirements of additional indepth study when necessary.

National Dam Safety Program. Johns Creek Number 4. (Inventory Number VA 04504), James River Basin, Craig County, State of Virginia. Phase 1 Inspection Report

Download National Dam Safety Program. Johns Creek Number 4. (Inventory Number VA 04504), James River Basin, Craig County, State of Virginia. Phase 1 Inspection Report PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 82 pages
Book Rating : 4.:/5 (227 download)

DOWNLOAD NOW!


Book Synopsis National Dam Safety Program. Johns Creek Number 4. (Inventory Number VA 04504), James River Basin, Craig County, State of Virginia. Phase 1 Inspection Report by : James A. Walsh

Download or read book National Dam Safety Program. Johns Creek Number 4. (Inventory Number VA 04504), James River Basin, Craig County, State of Virginia. Phase 1 Inspection Report written by James A. Walsh and published by . This book was released on 1979 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of a Phase I investigation is to identify expeditiously those dams which may pose hazards to human life or property. The assessment of the general conditions of the dam is based upon available data and visual inspections. Detailed investigation and analyses involving topographic mapping, subsurface investigations, testing, and detailed computational evaluations are beyond the scope of a Phase I investigation; however, the investigation is intended to identify any need for such studies. Based upon the field conditions at the time of the field inspection and all available engineering data, the Phase I report addresses the hydraulic, hydrologic, geologic, geotechnic, and structural aspects of the dam. The engineering techniques employed give a reasonably accurate assessment of the conditions of the dam. Phase I reports include project information, all existing engineering data, operational procedures, hydraulic/hydrologic data of the watershed, dam stability, visual inspection report and an assessment including required remedial measures.

National Dam Safety Program. Scotts Millpond Dam (Inventory Number VA 05706) Rappahannock River Basin. Essex County, Commonwealth of Virginia. Phase I Inspection Report

Download National Dam Safety Program. Scotts Millpond Dam (Inventory Number VA 05706) Rappahannock River Basin. Essex County, Commonwealth of Virginia. Phase I Inspection Report PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 51 pages
Book Rating : 4.:/5 (227 download)

DOWNLOAD NOW!


Book Synopsis National Dam Safety Program. Scotts Millpond Dam (Inventory Number VA 05706) Rappahannock River Basin. Essex County, Commonwealth of Virginia. Phase I Inspection Report by : James A. Walsh

Download or read book National Dam Safety Program. Scotts Millpond Dam (Inventory Number VA 05706) Rappahannock River Basin. Essex County, Commonwealth of Virginia. Phase I Inspection Report written by James A. Walsh and published by . This book was released on 1981 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scotts Millpond Dam consists of two earthfill embankments located on the left and right sides of a natural knoll. Scotts Millpond Dam is a 'small' size - 'significant' hazard structure as defined by the Recommended Guidelines for Safety Inspection of Dams. Visual inspection of the dam revealed several major deficiencies requiring further attention. The depth, duration, and rate of overtopping flows are considered detrimental to the right embankment and there is a high probability the embankment would fail if the SDF would occur. The spillway is adjudged as inadequate. The spillway is not adjudged as seriously inadequate since dam failure from overtopping would not significantly increase the hazard to loss of life downstream from the dam over that which would exist just before overtopping failure.

National Dam Safety Program. Falling Creek Dam (Inventory Number 01910), Roanoke River Basin, Falling Creek, Bedford County, Virginia. Phase I Inspection Report

Download National Dam Safety Program. Falling Creek Dam (Inventory Number 01910), Roanoke River Basin, Falling Creek, Bedford County, Virginia. Phase I Inspection Report PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : 47 pages
Book Rating : 4.:/5 (227 download)

DOWNLOAD NOW!


Book Synopsis National Dam Safety Program. Falling Creek Dam (Inventory Number 01910), Roanoke River Basin, Falling Creek, Bedford County, Virginia. Phase I Inspection Report by : ARMY ENGINEERING DISTRICT NORFOLK VA.

Download or read book National Dam Safety Program. Falling Creek Dam (Inventory Number 01910), Roanoke River Basin, Falling Creek, Bedford County, Virginia. Phase I Inspection Report written by ARMY ENGINEERING DISTRICT NORFOLK VA. and published by . This book was released on 1979 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pursuant to Public Law 92-367, Phase I Inspection Reports are prepared under guidance contained in the recommended guidelines for safety inspection of dams, published by the Office of Chief of Engineers, Washington, D.C. 20314. The purpose of a Phase I investigation is to identify expeditiously those dams which may pose hazards to human life or property. The assessment of the general conditions of the dam is based upon available data and visual inspections. Detailed investigation and analyses involving topographic mapping, subsurface investigations, testing, and detailed computational evaluatons are beyond the scope of a Phase I investigation; however, the investigation is intended to identify any need for such studies. Based upon the field conditions at the time of the field inspection and all available engineering data, the Phase I report addresses the hydraulic, hydrologic, geologic, geotechnic, and structural aspects of the dam. The engineering techniques employed give a reasonably accurate assessment of the conditions of the dam. It should be realized that certain engineering aspects cannot be fully analyzed during a Phase I inspection. Assessment and remedial measures in the report include the requirements of additional indepth study when necessary.