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HomeMy WebLinkAboutAGENDA REPORT 1995 0419 CC REG ITEM 11KITEM �•� PLEASE REFER TO THE MOORPARK REDEVELOPMENT AGENCY AGENDA PACKET FOR THE AGENDA REPORT FOR THIS ITEM 0016-1 AGENDA REPORT MOORPARK REDEVELOPMENT TO: Redevelopment Agency Boa-d From: Dirk Lovett, Assistant C _t,,,, Hn i -nee ITEM _ AGENCY No Date: April ?, 1995 Meeting o,- �-�j � i l 19, 1995) Subject: Consideration of remedia_ -f,ai t Wicks Detention Basin. BACKGROUND WICKS ROAD SETTLEMENT /� 11 Cam: / L �� Road and adj�,cent On September 23, 1994 the Engineering Department was made aware of some apparent new cracks along the southerly shoulder of Wicks Road. Engineering Staff anci their Geologist immediately investigated the cracks and potholed to determine if the cracks were of a superficial nature of o:r]d potentially pose a threat to the street or adjacent property. Bot.r. the City Engineer and the consultant Ge,Aogist shared the pa_rci..n that recent settlement has occurred and � hats f,irther ins e� t .g,;rt i.:m was necessary to determine the cause an:-1 extent of r ae ,F. ]E�iis nt, alon4 with remedial measures. On November 30, 1994, the Ci -t cf Moorpark authorized A.G.I. Geotechnical to perform a geotechnical investigation of the distress and develop solutions. As a result, a report discussing the apparent cause along with ieir.e,_La". r<nd permanent solutions was provided to the Engineering DEp,tt'meat f review. In addition, ,chile performing a i_:tfEr -n investigation, relating to substandard housing at thf -, 5 r ,,r ,his same slope, the City Engineering Department disc• c�r�.�c: that some non- approved excavations have- taken place_ th( ce which pose additional potential hazard: rc both the s',, - ,' the homes below. DETENTION BASIN The subject detention basin, __ocated between Wicks Road and Everett Street (See Exhibit 1) , was c, )nstruct.ed by the Army Corps of Engineering some fifty year Research determined that no additional history or plans -,f hF, - ; >r,': >truction .:are available at the City or Cc;unty. In years tyre basin drained onto Everett Street belov� 7'.a an undergroi t,_xn that outlets through a retaining way_ . ^he pipe syst ens obstructed and water backs up in the basin afte > i;,, �_i. it can evaporate or percolate into; the soil . Since ;_;ararneters of the basin are unknown here are risk:, it c with water backing up including water breaching the t_ 1 -hi- oasin anc adverse impacts due to increased hydrostatic �rF;.�,r� tiwooerties below. 1 00007 Wicks Road currently serves, :)r iaL, the potential to serve, 21 lots (10 of which are vacant, 10 of have single family homes, and 1 which supports 18 separate dw(-lling !;nits) . The SP -10 property, to the north and east, has a pots ?ntial for the development of between 154 and 231 homes. It: i;, possible that Wicks Road may necessarily be extended to pr�>,Tidel a secondary access to that development at some time in the :',rt 1F= i,efer to Exhibit 1 ). This report provides option., ic:vantages, disadvantages, and preliminary cost estimates f -ar �o''; -}i,- settlement and detention basin problems, . DISCUSSION WICKS ROAD SETTLEMENT There is no indication that the- )hser -ed settlement cracks were caused by an incipient landsli-3t. Rather it is the geologist's opinion that the distress is die to >ver watering and lack of support of the poorly consolidated <,houder material. It was also observed that the fill mater:._a- r the slope was not compacted to current standard:. and is subjE,cr . , -,-ot on. and surficial failures. Two repair options have been re:-I.7mmendt�.d by the geologist and are being submitted herein for thF, �'��i�- _- pproval_: Remedial Repair The remedial ,solution involves l,.1irn..nat-ng the existing irrigation system on the south side of W- -A.� Road, the sealing of cracks, grading of the southerly shoulder t_ redirect water away from the slope, placement of jute mesh and 3rought tolerant vegetation on the slope, an(! the installati.or :- >lc >ugh/ retaining wall at the toe of slope. Iehicles shoal a'.; ;revented from driving or parking on -hF sho al der at th ;. ; - � r Advantages: The advantage of the remeci , a , vroi -, is the cost savings in comparison to a permanent s( t r: Disadvantages: a. Remedial repair does not settlement should water from water line break) intrude int b. The possibility of future Utility rupture (water o:c acceleratF- settlement or property below. c. Continued maintenance anc im inat t:, the possibility of future anz soirce (irrigation, rain, or le s i1. se- dement increases the risk of has water line break could 'a ise a mud f low onto the ri1j. 2 "008 Permanent Repair A permanent solution involves t:­ removal and recompaction of the existing fill (see Exhibit 2),, ns!.allation of soil stabilization measures suer. as geotextile:,, st,&ilization material (soil cement) , and /or placement of j! rnesf, replacement of the road section, and i -i ti l i ty relocat.i,,n: Advantages: The permanent solution wou. reduce -he possibility of future settlement and, as such, any __otent.i� =.i utility ruptures. Disadvantages: a. The permanent solution i, erg expensive. b. Detouring and maintainin_,f local traffic will be difficult and inconvenient to resident; i* 'he and of the road. With either option the street ar;. houlcier repairs would be within the City's 50 foot right - of - -o, y Red ,airs to the slope would encroach onto private pro,3et, requiring construction and maintenance easements. DETENTION BASIN Two repair options have been and are being submitted herein for the Agency "s approval Storm Drain Only This solution entails replacemF-r.t )f -he existing standpipe and storm drain pipe and connection the :xisting storm drain system in Everett Street. Advantages: The benefit of the storm- drai;i ;nil >p..on is the cost savings. Disadvantages: a. Periodic maintenance would r�qui:ed. b. This repair does not facit.� future widening of Wicks Road. Storm Drain and Fill -In Basin This option involves the fill nor in ci the retention basin and installing a storm drain systeri from Wd (,ks road to the existing storm drain on Evere--t Street. Advantages: 3 66009 a. Additional land will be Wade usable and Wicks Road could be widened in the future wi,'ac,.jt t fi( installation of large retaining walls. b. Street and drain maint:en -::.c lli.� to debris and erosion in the basin, will be reduced. Disadvantages: The major disadvantage of tn. optio>i is the large construction cost. It should be noted that the deter:tion basin is located on property owned by adjacent residents. Ther_efDre the property would have to be purchased by the City or ) c is trlicl- i:-)n easement would have to be obtained. With either option the it is n(>t. known %✓hether the capacity of the Everett Street storm drain bel, will handle the increased load when the basin drainage is tied di, -ect .y into the Everett drain. Hydrological calculations will 1-)E- rF qul rF,d prior to any connection. FISCAL IMPACT The following cost preliminary >st es ._imates have been developed on rough pre - design assumption -.s ; r ,t -i c.ssion purposes only. WICKS ROAD SETTLEMENT COSTS Remedial Repair Engineering $4,500 Construction $25,000 Inspection & Admi ri trar -ion $4,000 Subtotal $33,500 25% contingency_. S8 500 Total $42,000 note: Periodic maintenance a:�)ciate with crack sealing and shoulder grading would be minima' i( a: nor been included. Permanent Repair Design Engineeri,, $15,000 Construction $250,000 Inspection & Administrat-ion $38,000 Subtotal $303,000 25% contingency- _ $76,000 TOTAL $379,000 4 0001'0 DETENTION BASIN COSTS Storm Drain Only Engineering $6,000 Construction $35,000 Inspection & Administration $6,000 Subtotal $47,000 25% contingenc-y_ _ 512,000 Total $59,000 Storm Drain and Fill -in Basin Preliminary Geot�-chrjic'al $11,000 Design Engineeri,? $19,000 Construction $640,000 Geotechnical Inspection $30,000 Inspection & Adm nistra ion 520,000 :subtotal $720,000 25% cot naen _— — $180,000 Total $900,000 FUNDING There are no available contribut ion:, tc aid in these repairs from previous developers on Wicks Road. Historically, developers have not paid for improvements to Wi:"ks Road other than constructing improvements along their property fwIcrtage ; ;. The necessary work under either ])tier may be funded by Gas Tax or Redevelopment Agency funds . ity Manager recommends Redevelopment Agency funds. Fij he. i i.• recommended that the appropriation for construction JeteYrEd until the earlier of the bid award or a ioptior� of the �( CONCLUSION Wicks Road Settlement It is the Geologist's opinion the observed road distress is due to excessive water from irri.gat_cn aid rain on poorly compacted soil material on the shoulder, signs of an incipient landslide have been observed however compa ~.._(> o, the supporting road fill are not up to 'uirent standards ci_ i�iact�e. The permanent solution to the road ement would rFC {.:_:F the removal and recompaction of a large of the hi L'. sir 1 I cud section at a very high cost. Even though the road shoulder ha- been �.00rly constructed and the slope fill is not up to current ,t.andarcls, less expensive remedial measures could be effectively 10111zed. The remedial measures do not eliminate the risk of futurE settlement or surficial slope instabilities but would impel -, t lot ?ntirely stop the adverse distress. The remedial repai_r� r 17 ~-e continued maintenance 5 00011 and monitoring but would effective;,, extend the usable life of the road until such time that the City, either decides to widen the road or sees the need foj the more per U r :- ePair. Detention Basin An effective solution to the ex_sring bstructed drain line would be to install an engineered ep_acement drain system, to be connected directly into the EverFt' SL-tEet storm drain below. This would serve the minimum needs o" a`,�t -. An alternative, and much iitorf -- -�,per,;jve, option would be to entirely fill in the basin, ex—ilding the storm drain discussed above to Wicks Road, This alt_rna w�)ild decrease maintenance to Wicks Road and the storm dr 111] a:, facilitate any future widening need,, for the road. RECOMMENDATION (Roll Call Vote) cc C Due to the large disparity in co,, E, the immediate effectiveness of the lesser options, and the ak >1: t >f the City to undertake the more permanent and expensive r i,, it any later time without significant cast waste due an', k �:)er,_ armed as part of the lesser option work, staff would re�c,iin. 11 It he AgE,ncy approve the following: Staff recommends the appropz, ition �f $11,500.00 from bond construction proceeds for th(- Ie ign of repaij to Wicks Road ($4,500.00), and the adjacer_t basin drain replacement ($6,000.00), with a contingen,:y rir .�JO Steve Kueny, City Manager Ken Gilbert,. Director of Pub_i 84.460 00 12 R- E M o v,- L- .41\1 �-o ivt pAcTlo M r � ••• ' • •• QaIQ •. le' • Qai z • Qal Oaf L M w a N f,9 MOORPARK Lujwitwkw EXNIBIti A� 5 Q O� �SP li 18 RS 43 POINDEXTER SUED. V_j 5 MR 5 4 M 7 ' 1, 36 P 19 1/2 mmm =� _T_lw A ffA LW'w A- (� AREA OF �F-FTLEMENT /DlISTRtSS DETENTION BASF( PCTENTIAL PROPEVFIES SERYED R,Y wiCI<S k o P\ D