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Home My WebLink About; La Costa Meadows Lot 693; Soils Report Preliminary; 1989-05-15i PRELIMINARY GEOTECHNICAL INVESTIGATION Single Family Building Site Site: Lot 693, Obelisco Circle La Costa Meadows, Carlsbad 15 May 1989 Prepared for Owner Mr. Jack Williams ENGINEERING DEPT. LIBRARY City of Carl&ad 2075Las Palmas Drive Carlsbad CA 92009-4859 Prepared by PROPERTY DEVELOPMENT ENGINEERS, INC. 1859 s. Escondido Blvd. Escondido, CA 92025 j43-8808 SHT 1 OF 20 - General Information... Lot Discription....... Natural Terrain....... Proposed Construction. Field Investigation ,. Recommendations....... Tests & Analyses...... ...... ...... ...... ...... ...... ...... ...... JOHN VERNON &ASSOCIATES 1859 S. ESCONDIDO BLVD. ESCONDIDO, CA 92025 TEL. (619) 743-8808 APPENDIX .......... ................ 3 of 6 .......... ............. 3 of 6 .......... .............. 3 of 6 .......... .............. 3 of 6 .......... .............. 4 of 6 .......... .......... 4&5 of6 .......... .............. 6of 6 Plate Appendix "A" - Location Map, Parcel 3................ Soil Discription (Figure l)...... Bearing Capacity Example.............. Unified Soil Classification Chart..... Foundation Requirements Near Slopes... Appendix "B" - Standard Specifications for Compacted Filled Ground Appendix "C" - Homeowners Maintenance Guidelines ........ ...... ........ ........ ........ .1 .2 .3 .4 SHT 2 OF 20 JOHN VERNON & ASSOCIATES 1859’S ESCONDIDO BLVD. ESCONDIDO, CA 92025 TEL. (619) 743-8808 May 16, 1989 Mr. Jack Williams 1433 Solano Street Carlsbad, CA 92009-7527 PRELIMINARY GEOTECHNICAL REPORT Site: Lot 693, Obelisco Circle La Costa Meadows, CArlsbad To whom it may concern: At your request our firm has completed a visual survey of the native soils at the above referenced site. It is understood that the anticipated development will consist of a single family residence. The structure is to be of wood frame and concrete slab floor construction, with commensurate soils loading. The natural terrain slopes to the east at an inclination of 6:l and is covered with a growth of native shrubs. Numerous small rocks are visable on the natural ground surface and several piles of rock and debris lie on the surface (a small berm has been dumped at the northwesterly frontage of the site). The native soil is a red brown silty sand (SM) and is not .detrimentally expansive. Generally the topsoil extends to a depth from 1' to 3'. Underlying the topsoil layer is a fractured yellow/red/brown bedrock. The bedrock is weathered atthe surface and becomes more dense with depth. No seepage was in evidence during the site inspection. The fractures in the upper surfaces of the rock are filled with clay soils which are known to be expansive. The prooased construction as shown on the above referenced elan consists -of a cut/fill pad with excavations of up to 5'- in vertical depth. The bedrock is probably excavatable with heavy equipment (DS Caterpiller) to a depth of 7' below the surface with more dense areas at deeper depths. . There are no known faults located close to the site (Rose fault is approximately 12 miles west. 30 miles NW). SHT 3 OF 20 PROPERTY DEVELOPMENT ENGINEERS, INC. S"R"EY,t.!G JOHN VERNON &ASSOCIATES 1859 S. ESCONDIDO BLVD. ESCONDIDO, CA 92025 TEL. (819) 743-8808 We recommend undercutting the pad in the vicinity of the residence to a depth of at least 3' and replacement with select or imported friable sand fill material. The resulting soil may be placed in the fill for the house at lower depths and the imported soil should be placed in the upper 3' of the house pad. Foundations should be founded in firm natural soil, rock or properly compacted embankment. The soils engineer shall review the footing excavations prior to concrete placement to ensure adequate foundation support. Footings shall be sized in accordance with Table 29-A of the Uniform Building Code and be 16" minimum depth. Isolated pier and spread footings may be sized for a maximum allowable soil bearing value of 2000 psf, but in no case shall they be less than 16" in smallest dimension. All footing trenches and slab subgrade should be maintained wet before concrete is cast. Continuous foundations shall be reinforced with two #4 bars at the top and two bottom of the footings. Square or round footings shall be reinforced in accordance with the structural engineer's recommendations, but in no case with less than E4 bars at 12" on center in each direction. Concrete slab floors should be reinforced with #3 bars at 10" on'center each way and be placed on a 4" clean compacted sand blanket. A vapor barrier of 6 mil visqueen should be sandwiched in the sand blanket under all indoor slabs. We emphasize that it is the responsibility of the contractor to insure that the slab reinforcement is placed at midheight of the slab. Experience indicates that use of reinforcement in slabs and foundations will generally reduce the potential for drying and shrinkage cracking. However, some cracking should be expected as the concrete cures. Minor cracking is considered norma~l; however, it is often aggravated by a high water/cement ratio, high concrete temperature at the time of placement, small nominal aggregated size, and rapid moisture loss at time of placement, due to hot, dry, and/or windy weather conditions during placement and curing. Cracking due to temperature and moisture fluctuations can also be expected. The use of low slump concrete not exceeding 4 inches at the time of placement is recommended. The contractor should take appropriate' curing precautions during the placement of concrete to minimize cracking of slabs. We recommend that a slipsheet or Semco Tile Set (or equivalent) be utilized if crack-sensitive flooring (such as SHT 4 OF 20 JOHN VERNON & ASSOCIA’I~E 1859 S. ESCONDIDO BL\/i: ESCONDIDO, CA 9202 TEL. (619) 743.800 marble tile or Mexican pavers) is planned directly on the concrete slab. All slabs should be designed in accordance with structural considerations and joints for induced contraction cracks should be considered to maxlmize aesthetic quality of hard floor coverings. Retaining walls both interior and exterior may be designed for an active pressure using an equivalent fluid pres.aure..~~~of 39 pcf. Retaining walls which are rigidly. fixed at the top or with sloping backfill should be designed for an active pressure using an equivalent fluid pressure of 59 pcf. Footings for retaining walls may be supported by an allowable bearing pressure of 2000 psf. Design resistance to sliding may be based upon an allowable passive pressure using an equivalent fluid pressure of 300 pcf. A coefficient of friction between the soil and the bottom of the retaining wall footing OS 0.38 may be used in resisting sliding also. All retaining walls shall be adequately drained, both at the top and at the bottom. The tops of all retaining walls shall have a drainage facility to prevent the erosion of the wall backfill. This facility should be a paved "V" or half tile ditch at the top of the wall, unless the soil or finished surface at the top of the wall slopes away from the wall. In addition, the wall must be designed, with an underdrain system consisting of weep holes, open head joints, or perforated pipe to prevent the build up of hydrostatic pressure behind the wall. All visible walls should be water proofed on the back side to assure good asthetics. A selection of protective panels is now available to protect the water proofing during backfill operations. SHT 5 OF 20 JOHN VERNON &ASSOCIATES 1859 S. ESCONDIDO BLVD. ESCONDIDO, CA 92025 TEL. (619) 743.6608 - TESTS AND ANALYSES of the prevalling foundation soils indicate the following.engineering properties: Angle of Internal Friction Apparent Cohesion Maximum Dry Density Optimum Moisture Expansion Index Unified Classification Active Soil Pressure (Restrained or Sloping bkfill) Passive Soil Pressure Coefficient of Friction Expansion Factor (very low) Bearing Design Value 310 380 psf 118 16.3 1.8 SM 39 psf/ft 59 " 436 ' .38 1.6 2000 The grading should be done in accordance with the approved Grading Plan, the Grading Ordinance of the City of Carlsbad, and the attached Standard Specifications for the Placement of Compacted Filled Ground. We will be available for prejob conference and certification testing at notification when the grading work is scheduled and at the time footing excavations are made. Expansive soil tests will be performed if necessary in the actual material as footing levels are reached in the manufactured fill. Preliminary tests indicate very low expansivity. %ohn E. Vernon RCE 21121, GE 858 Exp. g/30/89 SHT 6 OF 20 JOHN VERNON & AiSOClATES 1859 S. ESCONDIDO BLVD. ESCONDIDO, CA 92025 TEL. (619) 743.8808 APPENDIX "A" ,- SHT 7 OF 20 IACKHOE C =F: 62 : 0% q -o-- - ) 5-- IO - 15 p cl- 5- 10 - 15 i ‘/ = t E z 0 ;t el - : t ,RIAN HOOK I $7 g 0’: 0” 2; R- oUCKET SIZE: DATE: VW89 SOILDESCRIPTION TEST PIT NO. ELEVATION CH Residual silty clay with rock GM Red brown & tan silty clay matrix in rock fractured ! to blocky texture - Bottom @ 4.5 L iEST~ PIT NO. ELEVATION iOC3 OF TEST pITi!$ - d6CTNO. Williams Lot 693, Obelisco Circle, La Costa FIGVRE NO. 1 PROPERTY DEVELOPMENT ENGINEERS, I&C. SHT 9 OF 20 “PLATE 2” JOHN VERNON & ASSOCIA1’ltS 1959 S. ESCONDIDO BLVI). JOB # :1162-87 DATE : 05/10/1989 ESC3IhYDICJ?Y,KBI 9x025 JOB NAME: JOHN VERNON ASSOC. ,-SCRIPTION :TAN/ORG SANDY SILT/SILTY SAND ::MPLE : OBLIS, COTEL. (619) 743-8008 ***CAUTION*** THE BEARING CAPACITY SHOWN BELOW IS JUST ONE 'TOOL OF SEVERAL USED BY THE GEOTECHNICAL ENGINEER TO DETERMINE IF THE FOUNDATION IS ADEQUATE! Friction Angle (degrees)= 31 Cohesion (psf)= 380 Wet Density(pcf)=l22.3, Dry Density (pcf)=l84.7 Moisture Content(%)= 16.8 Factor of Safety= 3 LATERAL LOAD PARAMETERS ACTIVE PRESSURE (psf)= 39.1 PASSIVE PRESSURE (psf)=382.1 AT REST PRESSURE (psf)= 59.3 Ka= 0.32 IQ= 3.12 Ko= 0.48 COEFFICIENT OF FRICTION = 0.38 BEARING CAP(psf) DEPTfi/FTG. WIDTH/FTG. 2159.25 2193.92 2228.58 2263.25 2297.91 19.44 2384.1 2418.77 .2453.43 2488.1 1 1 1 1 1 L . 5 1.5 1.5 1.5 1 1.25 1.5 1.75 2 1 1.25 1.5 1.75 2539.63 2574.29 2608.96 2643.62 2678.29. 2729.82 2764.48~ 2799.15 2833.81 2868.48 2920 .Ol 2954.67 1.5 2 2 1 2 1.25 2 1.5 2 1.75 2 2 2.5 1 2.5 1.25 2.5 1.5 2.5 1.75 2.5 2 2989.34 3024 3058.67 NC= 19.4NQ= 9.3NG= 6.8 JOB # :1162-a7 LOCATI,ON :OBLIS Xl= 107 X2= 158 Fl= 32.1 F2= 47.4 Tl=‘--‘ 045.16 T2= 1543.32 ROOL MEAN SQUARE (RMS) ERROR IS PERCENT AGREEMENT T2 AND TB = 93 PROVING RING S.N.= 17016 FRICTION ANGLE = 31 co. x3= 294 F3= 88.2 T3= 2871.75 TB= 1654.02 : 51.2452 FR2= 31 CGHESION = 380 SHT 10 OF 20 3 3 3 3 3 2 c2= 436 .- 'B # :1162-87 .JOB NAME: JOHN VERNON ASSOC SOIL TYPE: 1 A= 211.6 R= 69.3 HI= 1 HA= 1 H2= 1 H3= 1.018 Assume Specific Gravity= 2.65 INITIAL CONDITIONS % water content=-8.01125 wet density = 112.443 dry density = 122.236 % saturation =-GO.1750 AIR DRY CONDITIONS % water content= 3.93534 wet density = 127.203 dry density = 122.463 8 saturation = 29.7723 ~-. SUBMERGED CONDITIONS % water content=-1410548 wet density = 103.39 dry density = 120.298 “PLATE 2 CONT’D JOHN VERNON &ASSOCIATES 1859 S. ESCONDIDO BLVD. ESCONDIDO, CA 92025 DATE : 05/10/1989 #jL. (619) 743-9008 SAMPLE: ORLIS CO. DESCRIPTION: TAN/ORG SANDYSILT/SILTYSAND Bl= 200.2 B2= 217.2 B3= 191.6 Jl= .397 IIS= .‘I15 WS= 142.3 DO= 2.373 Ring ID= 2.373 8 saturation =-99.4304 %'-YPANSION FROM AIR DRY To SUBMERGED CONDITIONS= 1.8 SHT 11 OF 20 JOHN VERNON & ASSOCIATES 1859 S. ESGONDIDO BLVD. ESCONDIDO, CA 92025 TEL. (619) 743-8808 JOHN E. VERNON, PRESIDENT RCE 21121, GE 850 CHUCK DAVIS, VICE PRESIDENT RCE 21719 FRED BRONSON. CHIEF OF SUAVEYS LS 5085 UNIFIED SOIL CLASSIFICATION CHART SOIL DESCRlPTlON MD,< man II‘,, 0, mrlerl., I‘ ,*rgcr ItI.“. NO. 200 I,#“8 GRAVELS. CLEAN GRAVELS si:;x CLEA,V scr:3s SW WellqaJce 52-,:. ~:J’rcii{ r3”dr. lillk 01 no h!3X Inan hall 01 CcuJr3? l‘Ji,ic’” is JmallC, man a no lines N3 L Iieir. SP Poorly praoel 3.21~5. ^rarelly raldr. lll!M or no liner. SANDS ‘,‘.‘ITH FINES SM silty Iandl. w,:iy c:a:ez ram3 am Ill!Y ,aDLl:cclable amounl, mixt”rCS~ SC Clayey sands. >aoliy graded IBM B”d clay mixture*. uon Vll” hall 0, nu,.dsl I‘ snu l,., lh.” ‘ No. 200 ‘la”* SILTS A&D CLAYS ML ,norganic SilX ml vr,-, line sa”ds.rOCk IlOU. sandy Sill an, cia,.e;.-sl!: ran0 mlxlures W!h a s%gh: p!ai’ ,:::, Liqu,3 Llrni, Less T&r- 50 LI;;., i;‘,:: .s;cr,e, ina;, 9 I_- __ WGHLY ORGCNC SOliS PROPERTY DEVELOPMENT ENGINEERS. INC. ENGlNEERlNG SOlL.5 TESTlNG . S”R”EYlNG SHT 12 OF 20 JOHN VERNON 81 ASSOCIATES 1859 S. ESCONDIDO BLVD. ESCONDIDO. CA 92025 TEL. (619) 7438808 JOHN E. VERNON, PRESIDENT RCE &2l, GE 858 CHUCK DAVIS. VICE PRESIDENT RCE 21719 FRED BAONSON, CHIEF OF SURVEYS LS 50-35 FOUNDATION REQUIREMENTS NEAR SLOPES RED”,“ED FOR L*TE”*L TYPICAL SECTION 5TA81L1T1 JG,IOWII<G P”OPOsLDFO”“O*T,O” COCATEO WlT,<,,, FCLT OF TOP OF 6LOi.E) 18” FOOTING / 5’ SETBACK TOTAL DEPTH OF FOOTING 1.6:l.D 6LOPE = zo:1.0 *LOPE 0 so- (8. 1. 61. 42. 2, 12. 10. 2. ,‘I- 1.3. “ ICJ’ :<- 7 __--- 0 rho” ..PI(FabI. FIGURE ““YnCn 100 N”MOL” \ SHT 13 OF 20 JOHN VERNON &ASSOCIATES 1859 S. ESCONDIDO BLVD. ESCONDIDO, CA 92025 TEL. (619) 7434008 APPENDIX "B" SHT 14 OF 20 ,. -- JOHN VERNON &ASSOCIATES 1859 S. ESCONDIDO BLVD. ESCONDIDO, CA 92025 TEL. (619) 743-8808 STANDARD SPECIFICATIONS FOR PLACEMENT OF COMPACTED FILLED GROUND Objective: Obtain filled ground which is uniform and has adequate internal strength to support any structures proposed. The method by which this is obtained is described herein. Preliminary Procedures: 2. 3. Permits - Owner shall ascertain the grading permit requirements of the agency whose jurisdiction covers the land on which the grading is to be performed and shall be responsible for complying with them. Water - An adequate water supply shall .be provided so t!lat compaction of filled ground will not be de.layed. Soils Engineer - A soils engineer shall be retained to provide direction in grading, testing for compaction and certification that the grading complies with grading ordinances and with approved grading plans. Grading: 1. Clearing and Grubbing - All natural surface which is to be covered by filled ground, excavated or needed for brow ditches, swales or other grading appurtenances shall be cleared and grubbed. Trees, shrubs and grass, as well as organic overburden shall be removed from the area to be graded. Cleared material may be disposed of as approved by the local controlling agency. No embankment shall consist of trees, shrubs or other organic material. 2. Natural Ground Preparation - Natural ground shall be excavated from beneath embankment areas to solid material, the exact depth as determined by the soils engineer. This material shall be brought to proper moisture content and recompacted to not less than 90% maximum density ZS determined by !J..s.T.F!/:. D-1557-70. SHT 1.5 OF 20 JOHN VERNON &ASSOCIATES 1859 S. ESCONOIDO BLVD. ESCONOIOO, CA 92025 TEL. (619) 743.600;s Any existing fill which has not been certified must be removed and recompacted. If the slope of the existing ground exceeds 1' vertical in 6' horizontal, a bench cut level, 10' wide shall be excavated at the toe of the fill. This will allow the embankment to be placed on a horizontal base for more uniform compaction. 3. Embankment Placement - Fill material should consist of native or importted materiai which has been broughr to the optimum moisture content. Material to be used for embankments may have rocks with diameters greater than 12': providing they are evenly distributed in the soil mixture and are at least 3' below finish grade. Fill slopes shall not consist of, *:I‘ be founded on, large rocks. Although rocks may be piaced alon3 the outside of the toe of rhe fill slopes. !?OCk placement: in embankments shall be under direct supervision of the soils engineer. Embankment.material shall ,be placed in layers varying from 6” to 12" deep depending on soil type, and compacted by suitable compactive effort co a density or not 1SSS than 90% of the max ;nzm density as determined by A.S.T.M. D-157-70. Moisture conrent and depth of layers shall be determined by the soil engineer at the time of grading, and shall be updated whenever embankment soil types change. As the embankment increases in elevation new benches shall be cut into original ground. Benches shall be at least 6: horizontally into natural ground, be level and shall occur at intervals to be determined by the soils engineer at the time of grading. Compaction may be obtained by the use of any combination of equipment which will result in an embankment that is properly compacted, uniform in moisture and properly finished to the lines and grades shown on the plans or to those set forth in Ihe applicable grading ordinance. 4. Additional Grading - Cut slopes shall be cut to the line-r, and ,grades as shown on Xhe pians or set forth in t5.e applicable grading ordinance. Cut slopes shall be protected from erosion by brow ditches. Brow ditches shall be either earthen or lined with erosion resistant material as shown on the plans or as recommended by the engineer. SHT 16 OF 20 JOHN VERNON &ASSOCIATES 1859 S. ESCONDIDO BLVD. ESCONDIDO, CA 92025 TEL. (619) 743.BBOB Embankments shall be protected from erosion by placing an earthen berm along the top of slope for the entire perimeter of the fill. Where drainage is brought down the slope, the.drainage way shall be lined with erosion resistant material to prevent loss of embankment slopes. Where eaves are located less than 5' horizontally from top of fill slopes, eaves troughs shall be provided to prevent weakening of slope due to water intrusion. All areas of the building pad must be well drained. Drainage swales shall have a minimum siope of 1' vertical in ii)0 I horizontal unpaved or 1' vertical in 200' horizontal paved rric.: concreTe. Drainage shall be provided to ensure foundations ;:I;.: not be subjecteci to ponde?i warcr. SHT 17 OF a, JOHN VERNON &ASSOCIATES 1859 S. ESCONDIDO BLVD. ESCONDIDO, CA 82025 TEL. (619) 743.8008 APPENDIX "C" .._- SHT 18 OF Zl JOHN VERNON & ASSOCIATES 1859 S. ESCONDIDO BLVD. ESCONDIDO, CA 92025 TEL. 1619) 743-8808 . MAINTENANCE GUIDELINES FOR HOME OWNERS -- HOMESITES, IN GENERAL, AND HILLSIDE LOTS, IN PARTICULAR, MAINTENANCE TO CONTINUE TO FUNCTION AND RETAIN THEIR.VALUE. HOMEOWNERS ARE UNAWARE OF THIS AND ALLOW DETERIORATION OF PROPERTY. IT IS IMPORTANT TO FAMILIARTZE' HOMEOWNERS WITH GUIDELINES ,FOR MAINTENANCE OF THEIR PROPERTIES AND MAKE AWARE OF THE IMPORTANCE OF MAINTENANCE. NEED MANY THEIR SOME THEM SOME GOVERNING AGENCIES REQUIRE HILLSIDE PROPERTY DEVELOPERS TO UTILIZE ~SPECIFIC METHODS OF ENGINEERING AND CONSTRUCTION TO PROTECT THOSE INVESTING IN IMPROVED LOTS OR CONSTRUCTED HOMES. FOR EXAMPLE, THE DEVELOPER MAY BE REQUIRED TO GRADE THE PROPERTY IN SllCH A MANNER THAT RAINWATER WILL BE DRAINED AWAY FROM THE LOT AND TO PLANT SLOPES so THAT EROSION WILL BE MINIMIZED. HE MAY ALSO BE REQUIRED TO INSTALL PERMANENT DRAINS. HOWEVER, ONCE THE LOT IS PURCHASED, IT IS THE BUYER'S RESPONSIBILITY TO MAINTAIN THESE SAFETY FEATURES BY OBSERVING A PRUDENT PROGRAM OF LOT CARE AND MAINTENANCE. FAILURE TO MAKE REGULAR INSPECTION AND MAINTENANCE OF DRAINAGE DEVICES AND SLOPING AREAS MAY CAUSE SEVERE FINANCIAL LOSS. IN ADDITION TO HIS OWN PROPERTY DAMAGE, HE MAY BE SUBJECT TO CIVIL LIABILITY FOR DAMAGE OCCURRING TO NEIGHBORING PROPERTIES AS A RESULT OF HIS NEGLIGENCE. THE FOLLOWING MAINTENANCE GUIDELINES ARE PROVIDED FOR THE PROTECTION OF THE HOMEOWNER'S INVESTMENT. 1. 2. 3. SHT 19 OF ?u SURFACE DRAINAGE MUST BE DIRECTED AWAY FROM STRUCTURAL FOUNDATIONS TO PREVENT PONDING OF STORM WATERS OR IRRIGATION ADJACENT TO FOOTINGS. CARE SHOULD BE TAKEN THAT SLOPES, TERRACES, BERMS (RIDGES AT CROWN OF SLOPES) AND PROPER LOT DRAINAGE ARE NOT DISTURBED. SURFACE DRAINAGE SHOULD BE CONDUCTED FROM THE REAR YARD TO THE.,STREET THROUGH THE SIDE YARD, OR TO NATURAL DRAINAGE WAYS WITHIN THE PROPERTY BOUNDARY. IN GENERAL, ROOF AND YARD RUNOFF SHOULD BE CONDUCTED TO EITHER THE STREET OR STORM DRAIN BY NONEROSIVE DEVICES SUCH AS SIDEWALKS, DRAINAGE PIPES, GROUND GUTTERS AND DRIVEWAYS. DRAINAGE SYSTEMS SHOULD NOT BE ALTERED WITHOUT EXPERT CONSULTATION. JOHN VERNON &ASSOCIATES 1859 S. ESCONDIDO BLVD. 4. ALL DRAINS SHOULD BE KEPT CLEANED AND UNCLOGGED ESCONDIDO, CA 92025 GUTTERS AND DOWNSPOUTS. TERRACE DRAINS OR GUN;T?%~%43S"o" SHOULD BE KEPT FREE OF DEBRIS TO ALLOW PROPER DRAINAGE. DURING HEAVY RAIN PERIODS, PERFORMANCE OF THE DRAINAGE SYSTEM SHOULD BE INSPECTED. PROBLEMS, SUCH AS GULLYING AND PONDING, IF OBSERVED, SHOULD BE CORRECTED AS SOON AS POSSIBLE. 5. ANY LEAKAGE FROM POOLS, WATERLINES, ETC. OR BYPASSING OF DRAINS SHOULD BE REPAIRED AS SOON AS PRACTICAL. 6. ANIMAL BURROWS SHOULD BE ELIMINATED SINCE THEY MAY CAUSE DIVERSION OF SURFACE RUNOFF, PROMOTE ACCELERATED EROSION, AND EVEN TRIGGER SHALLOW SOIL FLOWAGE. 7. SLOPES SHOULD NOT BE ALTERED WITHOUT EXPERT CONSULTATION. WHENEVER A HOMEOWNER PLANS A SIGNIFICANT TOPOGRAPHIC MODIFICATION OF THE LOT OR SLOPE, A QUALIFIED SOILS ENGINEERING CONSULTANT SHOULD BE CONTACTED. a. IF THE HOMEOWNER PLANS MODIFICATION OF CUT OR NATURAL SLOPES WITHIN HIS PROPERTY, A SOILS ENGINEERING CONSULTANT SHOULD BE CONSULTED. ANY OVERSTEEPENING MAY RESULT IN A NEED FOR EXPENSIVE RETAINING DEVICES. UNDERCUTTING OF A TOE-OF-SLOPE WOULD REDUCE THE SAFETY FACTOR OF THE SLOPE AND SHOULD NOT BE UNDERTAKEN WITHOUT EXPERT CONSULTATION. 9. IF UNUSUAL CRACKING, SETTLING OR EARTH SLIPPAGE OCCURS ON THE PROPERTY, THE HOMEOWNER SHOULD CONSULT A QUALIFIED SOIL ENGINEER OR AN ENGINEERING GEOLOGIST IMMEDIATELY. 10. THE MOST COMMON CAUSES OF SLOPE EROSION AND SHALLOW SLOPE FAILURES ARE AS FOLLOWS: A. GROSS NEGLECT OF THE CARE AND MAINTENANCE OF THE SLOPES AND DRAINAGE DEVICES. B. INADEQUATE AND/OR IMPROPER PLANTING. (BARREN AREAS SHOULD BE REPLANTED AS SOON AS POSSIBLE.) C. ~EXCESSIVE OR INSUFFICIENT IRRIGATION OR DIVERSION OF RUNOFF OVER THE SLOPE. 11. HOMEOWNERS SHOULD NOT LET CONDITIONS ON THEIR PROPERTY CREATE A PROBLEM FOR THEIR NEIGHBORS. COOPERATION WITH NEIGHBORS COULD PREVENT PROBLEMS, PROMOTE SLOPE STABILITY, ADEQUATE DRAINAGE, PROPER MAINTENANCE, AND ALSO INCREASE THE AESTHETIC ATTRACTIVENESS OF THE COMMUNITY. SHT 20 OF 20