Geotechnical Engineering Office GEO Circular No. 15 - Hong Kong ...

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -1. PURPOSERegistration and Updating of Date 1.7.2004Records of Features Page 1 of 201.1 This Circular details the policy and procedures for registration and updating of records ofsizeable man-made slopes, retaining walls, disturbed terrain and natural terrain hazardmitigation measures (collectively termed features). This revision covers the latest changesin the registration procedure to speed up the process of registration and updating offeatures in the Slope Catalogue. It takes into account the recommendations on registrationof features in the Director of Audit Report No. 38 – Chapter 10: Slope safety and landslippreventive measures, and the inclusion of natural terrain hazard mitigation measures inthe Slope Catalogue as agreed by the Standing Committee on Slope Safety.1.2 Any feedback on this Circular should be referred to the Chief GeotechnicalEngineer/Slope Safety (CGE/SS).2. POLICY2.1 The Slope Safety (SS) Division of the GEO maintains a catalogue of sizeable man-madefeatures for use in the Landslip Preventive Measures (LPM) planning andimplementation, slope maintenance and dealing with slope safety related issues, and foraccess by geotechnical practitioners and the public. In order to have this Catalogueupdated and maintained, GEO Divisions and their Consultants who deal with the featuresin discharging their duties are required to provide updated information they obtain on thefeatures and to report new, modified or “missed” sizeable features for registration to theSS Division as stipulated in this Circular.2.2 As agreed by the Standing Committee on Slope Safety on the need for regular inspectionand maintenance of natural terrain hazard mitigation measures, these features (i.e. themitigation measures) should be registered in the Slope Catalogue with a responsible partyand maintenance agent identified by the Lands Department in the SIMAR register.3. RELATED DOCUMENTS3.1 CEDD Operation Procedure OP-13 - Slope Catalogue Updating and Maintenance.3.2 District Practice Note No. PN 107 - Registration of Slopes and Retaining Walls.3.3 District Practice Note No. PN 131 - Provision of Information for Registration ofUnregistered Features.3.4 Environment, Transport and Works Bureau Technical Circular (Works) (ETWB TCW)No. 29/2002 – Geotechnical Control for Slopes and Retaining Walls.3.5 GEO Circular No. 30 - Stage 1 and Stage 2 Geotechnical Studies of Slopes and RetainingWalls.3.6 GEO Report No. 68 - The New Priority Classification Systems for Slopes and RetainingWalls (1998).[d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Registration and Updating of Date 1.7.2004Records of Features Page 2 of 203.7 GEO TGN No. 15 – Guidelines for Classification of Consequence-to-Life Category forSlope Features.3.8 Geoguide 5 - Guide to Slope Maintenance.3.9 Practice Note for Authorised Persons and Registered Structural Engineers (PNAP) 168 -Registration of Slopes and Retaining Walls, Buildings Department.3.10 Works Bureau Technical Circular (WBTC) No. 13/99 - Geotechnical Manual forSlopes – Guidance on Interpretation and Updating.3.11 Works Bureau Technical Circular (WBTC) No. 9/2000 - Registration and Updating of theCatalogue of Slopes.3.12 Works Bureau Technical Circular (WBTC) No. 16/2001 - GEO Checking Certificate forSlopes and Retaining Walls.4. DEFINITIONS4.1 Class A Features --- see Annex GC15 A1.4.2 Consequence Category --- Definition given in WBTC No. 13/99.4.3 Computerised Slope Register and Location Plans (CSRLP) --- The CSRLP is aDigital Slope Map System which contains the feature boundaries, registration numbersand basic map details in 1:1,000 scale and is maintained by the Survey Division of theCEDD.4.4 Feature --- A feature is (i) a slope or a retaining wall, or a combination of both, (ii)disturbed terrain, or (iii) natural terrain hazard mitigation measures. The criteria forfeature registration, the types of features not fit for registration (see 4.8 below) and thefeature registration system are defined in Annexes GC15 A2 and GC15 A4.4.5 Landslide Database (LD) --- A computerised database of the landslip incidents reportedto the GEO.4.6 Landslip Preventive Measures Information System (LPMIS) --- A computeriseddatabase system containing information on studies and upgrading works on slopesincluded in the Landslip Preventive Measures (LPM) Programme.4.7 Natural Terrain Hazard Mitigation Measures (NTHMM) --- Natural Terrain HazardMitigation Measures are classified into two categories for registration in the SlopeCatalogue. They are Stabilisation Measures (NS) and Defence Measures (ND). Theregistration system is defined in Annex GC15 A4.4.8 New Priority Classification System (NPCS) --- The NPCS is a system for prioritisingfollow-up LPM action on features in the Slope Catalogue.[d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Registration and Updating of Date 1.7.2004Records of Features Page 3 of 204.9 Non-Registrable Features --- Features which by their dimensions and/or type do not fitthe criteria for registration are set out in Annex GC15 A2.4.10 Slope Catalogue --- The inventory containing pertinent information of sizeableman-made features in the Hong Kong Special Administrative Region (HKSAR).4.11 Systematic Inspection of Features in the Territory (SIFT) --- A project that formedpart of the SIRST project. It was undertaken by the Planning Division and its Consultantsto identify registrable features in the HKSAR using Aerial Photograph Interpretation(API) techniques and existing topographic plans. The project was completed in June1997.4.12 Systematic Identification and Registration of Slopes in the Territory (SIRST) --- Aproject that collected and retrieved information on sizeable man-made features in theHKSAR. This project was commissioned in July 1994. The first part was the SIFTproject as described in 4.11 above. Site inspections were then carried out on the identifiedfeatures. Slope field data were collected including updating of field sheets for features inthe 1977/78 Catalogue of Slopes, registration of all newly discovered features, updatingof modified features and collection of NPCS parameters. The SIRST project wascompleted in September 1998.4.13 Slope Information System (SIS) --- The SIS contains computerised informationincluding the slope field data, the digital slope map from CSRLP, landslip incidents, GIUground investigation location data and other slope-related data. New layers addedinclude information on geology, natural terrain landslides, disused tunnels, districtinformation, horizontal drains, ground anchors, ducting for water-carrying services andLPM information.5. AUTHORITY AND RESPONSIBILITY5.1 The SS Division is responsible for updating and maintaining the Slope Catalogue and theSlope Information System (SIS). The SS Division also arranges training to GEO staff forusing the SIS.5.2 The Survey Division of CEDD is responsible for the upkeep of the digital slope map. Inthis connection, the Chief Land Surveyor of CEDD (CLS/CEDD) registers the boundariesof and assigns registration numbers to registrable features.5.3 The Landslip Preventive Measures (LPM) Division 1 is responsible for the establishment,updating and maintenance of the computerised Landslip Preventive Measures InformationSystem (LPMIS) and the Landslide Database (LD).6. PROCEDURE6.1 CHECKING OF FEATURE PRIOR TO REGISTRATION6.1.1 The criteria for feature registration and the types of non-registrable features are given in[d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Registration and Updating of Date 1.7.2004Records of Features Page 4 of 20Annex GC15 A2. The initiating GEO Divisions should check the information of thefeatures to be registered to ensure they are registrable and are not in conflict with otherregistered features prior to submitting them to the SS Division to carry out the registrationprocess. In case of any uncertainty in deciding whether a feature should be registered,CGE/SS should be consulted.6.2 REGISTRATION SYSTEM6.2.1 The registration system for features is given in Annex GC15 A4.6.2.2 When a feature is newly formed/constructed or identified and it meets the registrationcriteria, the responsible GEO Division/Project Department should request CGE/SS toregister the boundary and obtain a registration number for the feature. Only permanentfeatures and features with construction works substantially completed and the actualboundary determined will be assigned registration numbers; design proposals will not.The requesting party should follow the procedures in Section 6.3 below and submit therelevant information to CGE/SS. CGE/SS will then complete a Feature RegistrationNumber Request Form (Annex GC15 A6) and arrange with CLS/CEDD for assignmentof a registration number and updating of the CSRLP. Upon receipt of the registrationnumber and the updated Slope Location Plan from CLS/CEDD, CGE/SS will inform therequesting party and proceed with the slope cataloguing work.6.3 PROCEDURES FOR REGISTRATION AND UPDATING OF INFORMATION FOR THESLOPE CATALOGUE6.3.1 Private Features Checked by the GEO or Removed6.3.1.1 District GEs shall request the responsible AP/RSEs to submit the relevant feature data asstipulated in District Practice Note No. PN107 and PNAP 168 for all new features ornewly modified existing features which result from any private development especiallyfor site formation works and slope/retaining wall upgrading works.The District Divisions will provide a Checklist for Updating of Feature Records as shownin Annex GC15 A7 to the SS Division.The District Divisions shall ensure the following information is included:a) Boundary and location plans (1:1,000 scale) showing all new/modified features,existing features within and immediately adjacent to the site which have beenassessed as part of the development, and confirmation on whether these featuresare checked to current standard;b) Slope/Retaining Wall Records and a soft copy of feature data as per AppendicesC & D of PNAP 168 submitted by the AP/RSE; andc) A list of features that are removed as a result of the development.6.3.1.2 The SS Division shall ask for feature numbers from CLS/CEDD and inform the AP/RSEdirectly with a copy of the letter to the relevant District Division. CGE/SS will alsoadvise Lands Department in order that the maintenance responsibility shall be determinedor confirmed as appropriate.[d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Registration and Updating of Date 1.7.2004Records of Features Page 5 of 206.3.2 Public Features Checked by the GEO and Features Upgraded Under the LPMProgramme or Removed6.3.2.1 The responsible government departments or the relevant GEO Divisions are required toprovide information to CGE/SS under WBTC No. 9/2000 for all new features or modifiedexisting features or existing public features removed which result from any publicdevelopment works or LPM works. In accordance with ETWB TC(W) No. 29/2002, theboundaries of new features and modified existing features should be determined bysurvey.6.3.2.2 The SS Division will ask for new feature numbers from CLS/CEDD and inform therequesting department and the relevant GEO Divisions.6.3.2.3 To advance the process of registration of newly formed features, the Environment,Transport and Works Bureau (ETWB) requires project departments to forward the keyfeature information to CGE/SS for initial registration when the construction work hasbeen substantially completed and the actual feature boundary determined. The keyinformation includes the Feature Registration Number Request Form (Appendix C ofWBTC No. 9/2000), the preliminary slope/retaining wall key data (based on AnnexGC15 A9) and a 1:1000 location plan showing the boundary of the feature together withphoto(s) of the general view of the feature. Upon receipt of the information, CGE/SS willproceed to the initial stage of registration and CLS/CEDD will provide the digital featureboundary. Upon completion of the initial registration, CGE/SS will notify the projectdepartment or relevant District Division of the feature registration number and adviseLands Department in order that the maintenance responsibility would be determined orconfirmed as appropriate.6.3.2.4 When the detailed information becomes available, the project department will forwardthe information as per Appendix D of WBTC No. 9/2000 to CGE/SS. CGE/SS shall thenupdate the information of the newly formed features in the Slope Catalogue.6.3.2.5 For public features that have been checked by the GEO, the relevant District Divisionshall provide Checklist for Updating of Feature Records to CGE/SS as per Annex GC15A7.6.3.2.6 For features upgraded under the LPM Programme, the relevant GEO Division shallprovide the information as listed in Appendix D of WBTC No. 9/2000 to CGE/SS forupdating of the Slope Catalogue.6.3.3 Features Affected by Landslip Incidents6.3.3.1 Depending on the number of incidents, the LPM Division 1 will normally forward softcopies of the updated Incident Numbers and co-ordinates to SS Division at the end ofeach month, together with the registration numbers of the features affected by the landslipincidents.6.3.3.2 Depending on the number of incidents, the LPM Division 1 will normally provide softcopies of the landslip incident reports to the SS Division within 3 months after theincidents are reported by the District Divisions to them.[d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Registration and Updating of Date 1.7.2004Records of Features Page 8 of 207.4 GC15 A4 - Feature Registration System7.5 GC15 A5 - (Not used)7.6 GC15 A6 - Feature Registration Number Request Form7.7 GC15 A7 - Checklist for Updating of Feature Records on Private/Public Development7.8 GC15 A8 - Form for Suggestion for Improvement/Updating Information in SIS7.9 GC15 A9 - Preliminary Information for Registration of Unregistered Feature Identifiedby GEO Division7.10 GC15 A10 - Information for Registration of Natural Terrain Hazard MitigationMeasures( R K S Chan )Head, Geotechnical Engineering Office[d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Definition of Class A FeaturesRegistration and Updating of Date 1.7.2004Records of Features Page 9 of 20These are features considered to have similar circumstances to the Baguio Villas feature which failedcausing loss of life in May 1992, being either a fill slope or retained fill platform that fulfills thefollowing criteria :· assumed not to have been checked by GEO, i.e. interpreted from API to have been formedbefore formation of the GCO in 1977 or illegally formed, and not to be “Housing DepartmentFeatures”;· not to be “Features studied to Stage 2 or equivalent”, i.e. assumed not to have undergone aGEO Stage 2 study or equivalent, as identified from entries in the most recent updates of theLPM database;· situated adjacent to or traversing a natural drainage line;· judged to present a significant hazard, i.e. likelihood of failure in heavy rain;· judged to pose a high or very high consequence to life as defined by the Modified B&PAssessment of Consequence for Fill Features (as given in the Inception Report for Phase 2 ofthe SIFT Study) in the event of failure.Note that :-i) all five criteria must be met for a feature to be classified as Class A,ii )all fill features that pre-date the GCO, or are formed illegally, are assumed to be formedof uncompacted fill. These are likely to present a significant hazard when saturated, i.e.to have a likelihood of failure in heavy rain, regardless of whether or not they showsigns of distress (i.e. seepage, subsidence, cracking, bulging). However, if it isconsidered that there is no possibility of saturation of the fill during heavy rain byinfiltration, groundwater seepage or piping, or broken services and drains, the fillfeature may be judged not to present a significant hazard.GC15 A1 [1/1][d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Criteria for RegistrationRegistration and Updating of Date 1.7.2004Records of Features Page 10 of 20The criteria for features requiring registration are as follows :(i)cut slopes, including any associated retaining walls, and retaining wall greater than 3mhigh;(ii) fill slopes, including any associated retaining walls, greater than 5 m high;(iii) fill slopes, including any associated retaining walls, less than 5 m high which pose adirect risk to life i.e. Consequence-to-life Category 1 or 2;(iv) disturbed terrain features which contain repairs to landslide scars or comprise a series ofcomposite cut and/or fill slopes where the ground surface has been disturbed, the naturalslope gradient is greater than 15ºand although the individual slopes do not meet theheight criteria for registration, the total height does meet the criteria for registrations; and(v) natural terrain hazard mitigation measures are classified into two categories forregistration in the Slope Catalogue. They are:Note :(a)(b)stabilisation measures constructed on natural hillsides to prevent failure, e.g.boulder buttresses, soil nails and raking drains.defence measures to contain landslide debris and hence protect buildings andinfrastructure at the toe in case of landslide or boulder fall from the natural terrainabove, e.g. check-dams, earth bunds and boulder fences.1. A list of structures/features, which should not be registered in the Catalogue of Slopes,is given in the attached table.2. Disturbed terrain features generally covers situations such as repairs to landslide scars,cemeteries, cleared squatter land and agricultural terraces (existing or now abandoned)where extensive modifications have been made to the ground surface.3. Prior to March 1996, “Consequence-to-life” was referred to as “Risk-to-life”, and“Category 1”, “Category 2” and “Category 3” were referred to as “High”, “Low” and“Negligible” respectively in the Geotechnical Manual for Slopes.4. If the geometry of a hillside is substantially modified by earthworks (e.g. majorregrading), then the hillside is turned into a man-made slope feature. In such case, itshould be registered as a man-made slope feature.GC15 A2 [1/2][d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Registration and Updating of Date 1.7.2004Records of Features Page 11 of 20Types of Non-Registrable Structures/FeaturesStructure Type1. Seawall / marinestructures2. Dams and otherwater retainingstructures3. Basement walls /screen wallsDefinitionThe water-facing side of a coastal structure that retains soil or rockand is constructed of concrete, earth and/or rock.All water retaining structures including dams and service reservoirwalls maintained by WSD and private owners (e.g. Discovery Bayreservoir dam.). (Fill embankments in front of service reservoirs orother water-retaining structures should be registered.)Concrete walls that form part of a building and which are in directcontact with soil or rock, with the free air side facing into thebuilding.4. Tunnel/shaft lining Circular or other continuous concrete or steel walls or facingswhich are in direct contact with soil or rock. (Tunnel portal slopes/retaining walls should be registered.)5. Culverts / coverednullahsUnderground waterways. (Free standing sidewalls of opennullahs/catchwaters, catchwater slopes and river banks satisfyingthe registration criteria are considered as registrable features.)6. Bridge abutments The concrete / steel structure of a bridge that provides directsupport to the span of a bridge deck. (Fill embankments andreinforced fill structures and slopes should be registered.)7. All temporaryfeaturesFeatures under construction, e.g. temporary stock piles, quarryfaces and controlled tips. (Abandoned quarry faces andcompleted controlled tips should be registered as cut slopes andfill slopes respectively.)Note:Walls which are designed and constructed monolithic with a building or structure willnot be registered. Works departments/GEO Divisions should advise CGE/SS of suchwalls if they have already been registered in the catalogue of slopes.GC15 A2 [2/2][d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Registration and Updating of Date 1.7.2004Records of Features Page 12 of 20Feature Registration SystemRegistration Items Practice to be Adopted1. Feature Definitions F - Fill slope or platform with a surface sloping at ≥15º and a minimumfill thickness of 1m and without any associated retaining wall(s).C -R -Cut slope without any associated retaining wall(s).All retaining walls supporting a slope or platform with a surfacesloping at

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Registration and Updating of Date 1.7.2004Records of Features Page 13 of 20Registration Items Practice to be Adopted2. Marking of Feature R - plan boundary of the wallBoundaryF - boundary of the fill slope.C - boundary of the cut slope.FR – boundary of the slope and wall.CR – boundary of the slope and wall.DT – boundary of the disturbed terrain.NS – boundary of the natural terrain over which the stabilisation measuresHave been constructed.ND - boundary of the defense measures.GC15 A4 [2/2][d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Registration and Updating of Date 1.7.2004Records of Features Page 14 of 20Feature Registration Number Request FormSURVEY DIVISIONCIVIL ENGINEERING AND DEVELOPMENT DEPARTMENTPlease send this form to the Chief Geotechnical Engineer/Slope Safety of the GEO/CEDDPart I: RequestTo: Chief Land Surveyor / Civil Engineering and Development DepartmentProject/Contract:Locality:File Ref.:Type 1 : C / F / R / CR / FR / DT/ NS / ND *Approximate co-ordinates: N EStatus: Newly formed / identified / modified * (Existing feature no. )Date of formation:Plan no. 2 :Result required on or before:Remarks:Signature:Name & Post:Department/Company:Date:Tel. No.:Fax No.:* Delete as appropriate1 Refer Annex GC15 A4 of GEO Circular No.152 The plan should be in 1:1000 scale showing the location of the feature and with its graphical boundary highlighted.Part II: For CEDD Survey Division Use OnlyFile Ref.: ( ) in CEDD SY 9/3/301-( )Job No.:Instructions/Notes:1:1000 Map Area:Part III: ReplyTo:□AcceptedFeature No.:Slope Location Plan No.:Remarks:□ Not acceptedReason:Signed:Date:for Chief Land Surveyor/CEDDc. c. CGE/SS □CGE/I □ CGE/ME □ CGE/MW □ CGE/LPM1 □ □GC15 A6[1/1][d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -To CGE/SS (Attn. : SGE/ES)thro’ SGE/Registration and Updating of Date 1.7.2004Records of Features Page 15 of 20Checklist for Updating of Feature Records on Private/Public Development1:1 000 Scale Map Sheet Ref. :Location :District GE Area :District File Ref. :Name of Development Project :Name of AP/RSE/Geotechnical Consultant/Responsible Department* :Name of Contact Person/Post Title (for government officer only)* :Address:Section 1 : Information to be provided to CGE/SS when registered feature(s) has/have been checked upto current standard (Update to CGE/SS when necessary)Give registered feature no. and location plan indicating features/portions of features that have beenchecked up to current standard :#Registration No.Checked up to current standard1. Wholly/portion*2. Wholly/portion*3. Wholly/portion*----------------------------------------------------------------------------------------------------------------------Section 2 : Information to be provided to CGE/SS after the slope/retaining wall/natural terrain hazardmitigation measures (NTHMM) have been completedSlope/Retaining Wall/NTHMM Works Completion Date(month/year):(a) Are there any existing registered feature(s) removed under this development? Y / N(PleaseIf Yes, give registration no. and location plan :#circle)Registration No.Extent of removal1. Wholly/portion*2. Wholly/portion*3. Wholly/portion*GC15 A7[1/2][d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Registration and Updating of Date 1.7.2004Records of Features Page 16 of 20(b)Are there any existing registered feature(s) modified or partially modified tocurrent standard under this development?If Yes, give registration number, location plan and feature records and provide detailsbelow:#Y / N(Pleasecircle)1.2.3.Registration No.Details of modification (see note below)Note :For feature(s) partially modified, please provide details including feature registrationnumber, extent and type of modification on separate sheets. Please also indicate whether thefeature record covers the whole feature or only the modified part of feature.(c) Are there any new feature(s) formed under this development ? Y / NIf Yes, give location plan and records (Individual record is to be submitted for every (Pleasefeature) and provide details below:circle)1. No. of new features formed :2. New Registration No.:# 1.(for public development if known) 2.Prepared by : Post : datedChecked by : Post : dated----------------------------------------------------------------------------------------------------------------------* Delete as appropriate.# Use separate paper if necessaryNote to District GEs : (i) The District GE should check the latest information in the SIS for any affectedregistered feature(s) within the site.(ii) Northing/easting gridlines and the feature boundaries should be clearlyshown on the location plans.(iii) For Sections 2(a), 2(b) and 2(c), colour photos should be provided.(iv) Send copy to CGE/SS, keep original in District file at float.GC15 A7 [2/2][d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -To : CGE/SS (Fax No.2762 2389)Registration and Updating of Date 1.7.2004Records of Features Page 17 of 20Suggestion for Improvement/Updating Informationin Slope Information System (SIS)1. Suggestion for ImprovementCurrent Situation/Area to be improved:Suggestion for improvement:2. Updating InformationInformation to be updated : (e.g. Feature No., Feature Boundary, DH-Order...etc.)Current information in the SIS :Details of updated information to be included in the SIS :(Please continue on separate sheets if required)(Please provide supporting information and attach sketch if updated information relates to graphical presentation, i.e. featureboundary, feature sectional profiles...etc)Name and Post in Block Letters Division Contact Tel. No. DateFrom : CGE/SSTo:Suggestion implemented.Suggestion is not accepted becauseInformation updated as request.Information not updated/corrected as requested because( )for CGE/SSDateGC15 A8 (1/1)[d:\sge_es\circular15_1.7.2004][CHL]

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Registration and Updating of Date 1.7.2004Records of Features Page 18 of 20To: CGE/SSPreliminary Information for Registration of Unregistered Feature Identified by GEO DivisionFeature Type C / CR / F / FR / R / DT / Unknown *Location (Address)Date of Construction Formed or Modified pre mid-1978 / Formed or Modified post mid - 1978 / Unknown *Approximate Coordinates NorthingEastingSLOPE PARTMaterial Description Soil / Rock / Soil & Rock * Length (m)Max. Height (m)Type of WallWall MaterialMax. Height (m)Length (m)Average Angle (deg)WALL PARTRetaining wall with level platform / Wall at slope crest / Wall at slope toe / Wall at mid-slope*Random Rubble / Masonry / Concrete / Gabion / Others*Face Angle (deg)INFORMATION ON CONSEQUENCE-TO-LIFE CATEGORYFacility at Crest Building / Road / Open Area / Others *Distance of Facility from Crest (m)Facility at Toe Building / Road / Open Area / Others *Distance of Facility from Toe (m)Consequence-to-life Category 1 / 2 / 3* (Refer to Table 3 of WBTC No. 13/99)OTHER INFORMATION : (e.g. signs of distress, seepage, etc.) / REMARKS :ADDITIONAL INFORMATION TO BE PROVIDED :(a) Location plan (scale 1:1000) showing the boundary of the feature(b) Photo(s) showing the general view of the feature/ /Name & Post in Block Letters Division Tel. No. Date* Delete as appropriate, if 'Others' is selected, please specify.Note :1. Upon completion of registration, SS Division will return a copy of the 1:1000 plan indicating the registered number of the feature to theinitiating GEO Division.[d:\sge_es\circular15_1.7.2004][CHL]GC15A9

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -To: CGE/SSReference No. :Location (Address) :Registration and Updating of Date 1.7.2004Records of Features Page 19 of 20Information for Registration of Natural Terrain Hazard Mitigation MeasuresDate of Construction : Formed or Modified pre mid-1978 / Formed or Modified post mid - 1978 / Unknown *Approximate Coordinates : Northing EastingSTABILISATION MEASURESTypes of Measures :( Tick on thestabilisationmeasures asappropriate )□ Boulder Buttress Total Nos. of Individual Buttress :□ Soil Nails Total Nos. of Soil Nails installed :Max. Length of Soil Nails (m) :□ Raking Drains Total Nos. of Raking Drains installed :Max. Length of Raking Drains (m) :□ Others #DEFENCE MEASURESType of Measures : Check-dams Earth Bunds Boulder Fences Others #Length (m) :(for earth bunds and boulder fence only)Max. Height (m) :OTHER INFORMATION : (e.g. signs of distress, seepage, etc.) / REMARKS :ADDITIONAL INFORMATION TO BE PROVIDED :(a) Location plan (scale 1:1000) showing the boundary of the area covering the stabilisation / defence measures.(b) Photo(s) showing the general view of the stabilisation / defence measures.[d:\sge_es\circular15_1.7.2004][CHL]/ /Name & Post in Block Letters Department / Division Tel. No.Date* Delete as appropriate# Please SpecifyNote :1. Upon completion of registration, SS Division will return a copy of the 1:1000 plan indicating the registered number of thestabilisation / defence measures to the initiating GEO Division / Project Department.2. Depending on the exact locations of the 'stabilisation' measures constructed, different types of 'stabilisation' measures falling into the samelocation can be grouped together for registration purpose.3. Separate forms should be used for 'stabilisation' and 'defence' measures constructed.4. Separate forms should be used for each 'defence' measure constructed. GC15A10

Geotechnical Engineering Office Issue No. 3GEO Circular No. 15 Revision -Registration and Updating of Date 1.7.2004Records of Features Page 20 of 20[BLANK PAGE][d:\sge_es\circular15_1.7.2004][CHL]