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Overview
The Storm Drainage Master Plan (SDMP) summarizes the findings of an effort undertaken by the Los Trancos County Water District to map, document, analyze, and propose remediation for deficiencies in the storm drainage system of the Los Trancos Woods and Vista Verde areas of the District. The plan was completed and presented to the community in late October 2103 and in January of 2014 the District Board authorized formation of an ad hoc committee to perform an in depth review of the recommendations in the plan and to propose a path through which needed improvements could be undertaken. This committee report documents the results of the committee’s efforts through the end of March 2104 and lays the groundwork to begin more in depth discussions with the San Mateo County Department of Public Works (DPW) – a plausible partner for implementation.
The SDMP creates a comprehensive catalog of the pipes, gutters, drainage channels, inlet/outlet basins and other features of the drainage facilities in the communities and details the expected performance of each element under 10 year and 100 year expected storm runoff volumes. From this analysis, the report authors generated a list of 33 proposed projects that could be under taken to remedy both known and potential runoff issues.
The work of the committee integrates the technical analysis provide by the SDMP with the broader aspects associated with implementation including consideration of:

Easements for construction on private property

Impact of revised flows and discharge levels on surrounding areas
 Community aesthetics
 Design requirements utilized by the DPW

Financing
 Ongoing operations and maintenance
Each of these represent a part of the pragmatic environment that must be considered in conjunction of the pure engineering based conclusions that are embodied in the SDMP.
Examples of the challenges represented by these considerations are:

19 of the 33 projects would require an easement from a private property owner to permit a public entity to build and operate a part of the drainage system on that

Page 2 of 21 person’s property. For the projects proposed, 55 property owners would need to agree to easements.
 11 of the projects would increase or add new flows at 8 existing or new discharge points onto Blue “Oaks property. Exporting the problems from one part of the community has to be done in a way that does not cause problems in another community – and both communities must be in consensus that the solutions are appropriate.
 The design scope of the SDMP recommendations is based on the expected runoff from a storm which might occur once every 100years. The size, cost, and community impact of facilities that would handle this amount of runoff compared to the runoff expectations from a storm that might occur once every 10 years are much different. What is the correct level?
 What’s it like “on the ground”? Does a proposed solution solve the problems that have been experienced by residents in the affected area?
The body of this report that follows represents the information collected to date and the preliminary conclusions drawn from that effort. These are not final conclusions but will serve as a foundation to begin a dialog with the DPW. Additional data will be needed. The most important data will be information from residents in the community that will form the basis for making informed decisions on the projects that will be of most benefit to the community.
Constraints that Impact this study’s findings
The SDMP suggests a total of 33 projects as remediation for both reported and theoretical (100 year storm) drainage issues which could or currently do result in property damage issues. By virtue of several either/or project recommendations, the net at full implementation would be no more than 30 projects. The selection of projects which would produce the greatest short term remediation of risks currently faced by property owners in the community is complicated by a number of factors which will be briefly described in this section. Two factors, however, standout prominently at the head of this list and affect more than 2/3rds of the projects. These factors are: work that would need to be undertaken wholly or in large part on private property which includes private roadways; and new or substantially increased discharges onto property owned and maintained by the Blue Oaks Homeowners Association.
Private Property
A total of eighteen of the 33 projects are situated on private property to the extent that if implementation were undertaken by a public agency a grant of an easement from an affected property owner (or in most cases multiple owners) would, in most cases, be

Page 3 of 21 required. The San Mateo County Department of Public Works (DPW) has indicated a willingness to consider some such work under a scope and to construction standards normally employed by the County. Work on private property could also be implemented by a property owner or a group of owners who agree to share costs and liability for these implementations. In sum, 55 property owners would potentially be affected if all projects are considered. This constraint could prove to be a serious barrier to implementation of many of the recommended projects. In discussions with about 20% of the affected property owners, only one person has expressed an acceptance of the concept of granting an easement. Any of the projects that would be constructed across multiple properties would require 100% agreement in order for the project to move ahead. See Attachments 1, 3
Discharges onto Blue Oaks Lands
A total of eleven of the 33 projects will either increase discharges of storm drainage onto Blue Oaks lands and/or discharge onto Blue Oaks lands through newly constructed discharge points. The SDMP identified 4 existing discharge points onto Blue Oaks Lands and proposed 3 new points of discharge. Additionally this committee’s field reviews identified 1 additional point of discharge not described in the study located between
1008 and 1036 Los Trancos Road. Neither the current flow rates during storms of specific magnitudes nor the possible increased flow rates through these discharge points are described in the SDMP although the report does indicate that the design of the Blue Oaks drainage system was reviewed and should be capable of handling the flows.
The Blue Oaks HOA has expressed written concerns regarding the possible impacts of these flows to the Blue Oaks properties. While it does not appear that any of the new discharges could impact any of the privately owned portions of the Blue Oaks lands, the concern that the increased discharges across open fields prior to being intercepted by the Blue Oaks drainage facilities could cause erosion to trails, roadways or other land areas within Blue Oaks certainly has merit.
Given the tentative nature of commitment to the implementation and definition of any of the listed projects at this time, this committee believes that investing additional funds
(probably more than $15,000) to obtain specific project by project flow estimates is not merited. However, once a plan evolves that may implement a project or projects that would increase discharges onto Blue Oaks property, flow rate information should be developed and negotiations entered with the Blue Oaks HOA to address necessary mitigations through detention basins, bio-swales or additional culverts or other solutions to eliminate risks of damage to the Blue Oaks lands. See Attachment 2, 3

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Other Constraints
There are a number of other factors which will affect the path to implementation of the
SDMP. These factors apply uniformly to all of the projects and will affect any effort to implement the plan.
1.
Authority - To become the prime mover in implementation the District would need to establish its authority to construct and maintain such a system. At a minimum this would entail a very expensive and time consuming effort to activate latent powers or formation of some other type of district, with no certainty of success.
2.
Capabilities - Even if the District were to accumulate the funds necessary to execute any of the projects, the District is ill equipped to manage the design and construction efforts and would need to budget for additional necessary staffing.
Funding and managing ongoing maintenance responsibilities would need to become a part of a long term plan.
3.
Funding - Funding through loans or bonds in order to achieve a balance of financing for both construction and operations (bond money cannot be utilized for operations) does not appear to be possible for a district such as the LTCWD.
An inquiry through the California Small District Association financing arm indicated a very low probability of success. See attachment 5
4.
Design Scope - The San Mateo County Department of Public Works could assume responsibility for implementation of elements of the SDMP. The DPW, in general, designs storm drainage around less severe storm events (10 year to 30 year as opposed to the SDMP design criteria of 100 year) and also prefers to avoid long buried culverts that often result in maintenance difficulties. This would significantly change the nature of some of the designs.
5.
Community Aesthetics - The implementation of the plan suggests significantly wide and deep gutters and other surface structures which could create a visual impact as well as a roadway width and possible issues such as access to mailboxes for delivery. It is vitally important to not sacrifice the aesthetic appeal of the community in order to solve the storm drainage issues.
Area by Area Analysis
The SDMP breaks out project recommendations into 9 basin groups. This report will look at near term recommendations predicated on the constraints listed above by dividing the analysis into just 4 distinct areas. Three of these areas are located in and involve separable drainage almost entirely within the Los Trancos Woods area and stand out as distinguishable subareas when looking at a map of the recommended projects. The 4 th area is “everything else” and is entirely within the Vista Verde area of the community.

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Area 1
This area is comprised of basins A11, B10 to the extent that flows from residences on the West side of Ramona up to about 140 and sheet flow from Los Trancos Road onto Ramona is relevant, and basin B56. All of the recommended projects are located on Carmel or at the end of Chiquita.
Recommendations:
Much of the SDMP recommended work has already been carried out by residents in the area. The portion of Project 01 across the driveway at 144 Carmel has been built, a pipe running from the end of Chiquita to the creek has been built and a gutter (instead of the recommended pipe) from Carmel to the inlet of the pipe at the end of Chiquita is either complete or in process of execution.
 The portion of Project 01 to intercept flows from within the turnaround at the end of Carmel and conduct those flows at least down to the creek level if not all the way to the creek should be implemented.
 Project 02 should address the Curbs and gutters on Carmel between Ramona and Chiquita. The gutter on the South side has already been mostly improved with new construction but some remaining areas are probably undersized. The recommended curb on the north side of this section as well as the curbs along the balance of Carmel should be addressed to prevent off flow from the roadway flowing against residences.

Additional investigation in conjunction with the work on these curbs should address residents’ reports of flows along the alleyway that runs on west side of
111, 115 and 143 Carmel and then flow across 147 and 151 Carmel before being intercepted by pipe #223. This problem may be corrected by the curb between
103 and 111 Carmel or may be coming from another source.
 Residents also report that during periods of heavy rain some flow from gutters on Los Trancos Road flows down Ramona Road instead of continuing north on
LTR. The curb correction work on Carmel might also be expanded to address this issue so that all currently identified risks in this area have been addressed.
Area2
This area is comprised of basins C8, D7, all of basins E, F, and G, and basin B10 to the extent that residences along Ramona and Los Trancos Road are affected by flows off of
Los Trancos Road. This is perhaps the most challenging area in that it is comprised of 7 rows of residences split by 5 road structures. The runoff from relatively dense residential and outbuilding roofs as well as hardscape and roadways, according to residents, currently produces significant downslope sheet flows during periods of heavy rainfall. There are 5 points of discharge onto Blue Oaks property and 3 or more

Page 6 of 21 discharge points onto Ramona Road. Ten of the 33 SDMP proposed projects are located in this area.
Recommendations: Recommendations for project execution in this are heavily influenced by considerations of the constraints outlined previously.

Project 29B and Project 31 in combination with Project 03 export considerable quantities of storm water to Blue Oaks property through considerable distances
(600’ to 700’each) of buried storm drain piping. Both of these factors raise the pragmatic consideration of being able to undertake these projects in the face of possible resistance as suggested by the known constraints. Therefore, the recommendation, at this time, is to implement other less aggressive solutions and explore possible alternatives to these 2 recommendations. The Downslope curb and gutter improvements portion of Project 31 and the link of these curbs to Project 03 needs to be evaluated. There is a need to assess if properties 1051 –
1087 LTR are affected by spill over from LTR during heavy rains. Other risks carry as far as lower Carmel
 Project 03 may be useful to carry some of the flow which may overload the undersized newly relocated outfall at 1036 LTR. Instead of being designed to carry flows down to and through the intersection of LTR with Ramona it may be better to utilize the gutter discharge point located between 1008 and 1036 LTR.
This gutter discharge into Basin BO33 is not documented in the SDMP. Pipe 266 on Blue Oaks appears to be adequately sized to handle substantial flows. The point where this discharge enters Blue Oaks propitiates is substantially eroded for ~100’ and should be repaired using the plastic mat reinforced swale design used elsewhere throughout Blue Oaks.

Project 29A suggests rebuilding and burying the pipeline that currently runs from
~1207 LTR to 108/112 Foxwood. Again, constraints regarding DPW concerns about maintenance issues with long, buried storm drains and the bigger issue of gaining consensus for easements among 4 property owners suggests that a modified approach to 29A be considered. (Note that replacement of the uphill end or this pipe and undergrounding the balance of the pipe would entail considerable removal and replacement of existing hardscape, some outbuildings, as well as landscaping and possibly affecting some trees.) A modified approach would entail investigation and correction of any possible blockages near in the inlet (County owned) portions of this line and residents working together to correct maintenance issues on the balance of this line which from a capacity standpoint is deemed adequate for a 100 year storm per the SDMP analysis.
DPW may need to invest additional time to better understand where downhill flows producing problems at 108 Foxwood are originating. Resident reports that

Page 7 of 21 there were no problems with this pipe during 12/ 2012 storms. A possible alternative to residential maintenance of this line might be explored with DPW in the form of providing DPW with easements to maintain the line in the current above ground manifestation.

Projects 25 and, 28 would upgrade curbs and gutters along all of Los Trancos
Circle and Los Trancos Road from 1144 to 1207 to reduce downslope sheet flows that have been reported to be causing residential damage in some areas of Los
Trancos Road near the intersection with Foxwood. These two projects may be the two most import short term actions related to implementation of the recommendations of the SDMP. The size of the gutter suggested in Project 25 versus curb height may need to be given some consideration so as to not produce untenable narrowing of the usable road width and/or aesthetic issues.
The scope of Project 28 should consider extending curb installation along the
North West side of LTC from 124 to the intersection with LTR in view of some problems with sheet flows crossing the road and flowing across the property at
1148 Los Trancos Road. Also, the gutter on LTC across from 1148 LTR is probably under capacity in some short stretches. These two projects could produce some modest increases in discharges onto Blue Oaks Land so negotiations with Blue
Oaks should be undertaken to mitigate any possible erosion problems and possibly install detention structures to modulate peak flows. Proceeding with these curb and gutter improvements is recommended. See Project 27.

Project 27 as described in the SDMP would involve installation of more than 300’ of 15” pipe to carry the discharge from the intersection of LTR and LTC to a new discharge point on Blue Oaks lands. At present this discharge runs in an eroded
18’ deep channel for about 50’ almost due North across 1148 LTR and under a fence onto 1144 LTR and thence along a stone lined channel for ~150’ to a 12”
PVC pipe running steeply downhill for about 100’ onto Blue Oaks land. The owner of 1148 LTR is willing to grant an easement to improve the present channel but does not want to grant an easement for the much longer solution. A mesh lined swale such as extensively employed throughout the Blue Oaks property would possibly be a good alternative to a pipe at this location. Project
27 in itself would not change discharge quantities onto Blue Oaks and the discharge point would remain the same if the solution described above were to be implemented. A mesh lined swale and or detention basin on the Blue Oaks property should be considered as a mitigation of increased discharges related to
Projects 25 and 28 that would flow through this project.

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
Project 23 is entirely on private property (Foxwood plus the relocation of the discharge through a pipe through 135 Foxwood). With no information in regards to the existence or severity of any problems associated with this flow path, no recommendations are possible at this time. It does appear that utilization of the existing privately constructed channel starting near Foxwood, crossing over 115
Foxwood and then exiting onto Ramona through a concrete channel already constructed by DPW on 152 Ramona may be a an alternative worthy of consideration. See attachment 4.

Projects 30 and 30B are relatively low priority projects. Project 30 would correct problems with flows from the end of El Nido that exit the roadway into a rather deeply eroded channel and then flow across 144 El Nido toward Blue Oaks property. This flow path beyond about 10’ from the road has not been investigated and no discussions have been undertaken with the property owner.
Project 30B as an alternative would reroute flows from El Nido down LTC. Due to risks inherent with adding flows to an already problematic area this project is not recommended.

Project 24 would address replacing pipes 208 and 209 which are substantially undersized according to the SDMP calculations. The SDMP does not appear to address the discharge path for these pipes across one or all of the properties located at 153, 159, and 163 Ramona. Pending analysis of the pipes that are purported to carry this discharge across these properties to Los Trancos Creek, this project has no recommendation.
 Alternative to Projects 29B, 31, and 23. These 3 projects involve installation of considerable buried storm drainage piping and new construction on private property as well as exporting considerable flow from Basin E to outfalls on Blue
Oaks lands. Although less desirable to some property owners in the immediate vicinity of Foxwood Road a less aggressive solution involving rehabilitation of two existing drainage channels that run from the general vicinity of the intersection of LRT and Foxwood through private property to discharge locations on Ramona and eventually into Los Trancos Creek may warrant consideration.
These two channels (See attachment 4) are generally well constructed but are in a state of disrepair in some areas and also have apparently been interdicted by newer hardscape construction in some areas causing well controlled flows to be dissipated over broader areas and leading to some property damage threats.
Area 3
This area is comprised of all of Basin H, Basins Z58 and Z4 including the Frog Pond and the water district lake as well as the location of the recent slide repair on Ramona Road.

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A very important aspect of prioritizing projects in this area is making a determination of possible solutions involving redirection into the Frog Pond and/or the water District lake of the considerable flows that currently move downhill under Ramona Road into Los
Trancos Creek.
Recommendations

One of the primary decisions to be considered in this area is the tradeoff between Project 14A and the combination of Projects14B, 11A, 11B, &11C.
Either of these projects would correct a long standing problem of poorly controlled flows from Old Spanish Trail across private properties on El Rey. It should be noted that residents indicate there is an undocumented, probably
8”pipe connecting the east end of pipe 163 to the west end of pipe 250.
Residents indicated that the storms of 12/2012produced only minor problems with some water flowing across the driveway at 44 El Rey and some minor erosion. Erosion at the discharge point on the east side of El Rey from approximately 20’ before water flow enters a concrete lined ditch is also an issue that needs monitoring. Project 14A requires almost 650’ of 15” pipe from OST through private properties with significant landscape and hardscape to discharge onto District lands at the level of Lake Road. A detention basin to modulate flows into “Spanish Creek” would be constructed at the intersection of Lake Road and LTC. Conversely, Project 14B, 11A, 11B, 11C would divert most or all of the problematic flow instead down OST through a combination of pipes, curbs, and gutters to discharge into either/or the Frog Pond or the District lake. A possible variation of this design would be to cause the flow on OST to exit the roadway at approximately the North West corner of 56 OST and flow in a bioswale parallel to OST and eventually discharge into the District lake. A bioswale would clean up possible pollutants in the flow and maintaining the lake at or near capacity would augment the size and biodiversity of the lake as an ecofriendly wet land.
Any solution such as this would be dependent on all parties agreeing that this would be a sound and ecologically advantageous use of the storm water flow. In view of the relatively low level of problems associated with the current installation, this pair of project is of only moderate priority. In as much as the
14B solution would be mostly on publically controlled space, require much shorter buried pipe runs, and has ecological advantages, Project 14B is probably the best solution to be considered for eventual implementation. Note the impacts of Project 14B on Project 15.

Project 15 would improve flows from District property at the intersection of Lake
Road and LTC across LTR and eventually discharge under Ramona at the site of the recently repaired slide. It should be noted that if Project 14B is implemented,

Page 10 of 21 the flows through this channel would be substantially reduced. If Project 14A is implemented including the proposed detention pond, peak flow would also be reduced. One property owner between LTR and Ramona has indicated some concerns about erosion that is occurring in one part of the stream bed. The project proposes the installation of almost 800’ of buried storm drain beneath an existing semi improved ditch. Some property owners abutting this project have indicated that they probably would not grant an easement for this project. In view of the possible resistance from property owners, the concerns that would arise regarding maintenance of long, buried storm drains and the opportunities to substantially reduce flows in this drainage path through the implementation of Projects 14B or 14A, it is recommended that his project not be addressed at this time.

Projects 12, 16, 19
These projects would intercept flows from gutters on LTR Southeast of Bonita and on Visa Verde to and beyond the intersection with LTR north to the driveway accessing 1245 LTR. Some of these flows on the 152 LTC and 1244side of LTR through Project 19 improved gutters would continue north on LTR to flow into
Spanish Creek. The flow on the Southwesterly side of LTR and from Vista Verde would continue down the Southeasterly side of LTR to the driveway at 1243 or1245 LTR, down that driveway into an exsisting18” pipe, under the driveway and then under an adjacent fence into a rock lined ditch and down to Ramona
Road at the juncture with Spanish Creek. The proposed gutters are very large and would reduce the width of LTR between Bonita and Vista Verde by as much as 6’ and probably inhibit on street parking and possibly necessitate warning barriers of some design to prevent drivers from driving into the gutters.
The Project 16 element would install a gutter down the driveway at 1243 or
1245 and then a 30” pipe for almost 300’ in place of an existing rock lined ditch to a new discharge onto Ramona south of the current discharge at Spanish
Creek.
At least one of the residents that would be key to implementation of the private property aspects of this complex of interrelated project has indicted a strong opposition to granting a necessary easement. This would suggest that a much more modest set of solutions be investigated. An onsite inspection would suggest that more modest, drivable gutters on the uphill sides of LTR in combination with rolled curbs on the downhill side could be used to direct most of the street flows down LTR to an inlet at Spanish Creek. Increase in flows down the driveway at 1243/1245 LTR should be avoided. A low berm at the base of the driveway to 1245 LTR should be added to prevent flows down the driveway from

Page 11 of 21 escape beyond the diversion under the fence to 1243 LTR. The rock lined ditch that extends from the 18” pipe under the driveway at 1245 LTR down to Ramona and then, after a 90 degree bend, flows north to a discharge into Spanish Creek at Ramona appears mostly adequate. DPW should augment the ditch capacity at the point of the 90 degree bend (which is in the County ROW) by increasing the height of the ditch wall at that point to prevent overflow due to the high velocity of the flow at the point of the bend. The proposals for this area need to be reassessed in view of a less than 100 year storm design criteria and no availability of needed easements.

Project 17 recommends additional work to improve the inlet and outlet aspects of the pipe that transports the flow of “Spanish Creek” under Ramona Road at the location of the recently repaired landslide. The County DPW has implemented corrections to insure the proper function of this pipe. No action of this project is recommended.
 Project 21 proposes to extend the pipe from the outfall from the gutter on El Rey downslope across private property to the level of Lake Road. There is moderate erosion around the outfall which could be mitigated with some rock rip rap. No action recommended pending assessing property owners interest in granting an
 easement.
Area 4
This area comprises all of Vista Verde with the exception of the flow component across 205 Old Spanish Trail described in Area 3 Projects 14A, 14B.There are eight projects recommended in this area all of which have no interdependencies and have no dependency on projects in any of the other 3 areas previously described.
Recommendations

Project 4 proposes to construct a pipe from the Northeast end of Las Piedras crossing private properties and Vista Verde, eventually discharging into pipes
#128 and #129 onto private property at 333 Ramona. Pipe 129 is not properly documented in the SDMP and actually through as series or about ~400’ of 12” pipe and 35’ of open gutters flows across 333 and 319 Ramona and continues through pipes to discharge into Los Trancos Creek. Field checking has not been done regarding this project to determine the existence of any current problems.
It is reported that flows currently run down the driveway at 45 Las Piedras and through pipes to discharge onto pipe #120. This flow path is not verified. Pending

Page 12 of 21 field checking regarding any actual problems no action is recommended on this project.
 Project 5 proposes to increase the capacity of pipes near the intersection of
Ramona and Vista Verde and the pipe which possibly crosses private property at
400 Ramona Road. There are no reported issues related to the capacity of these pipes. The actual location of the pipe that may cross private property at 400
Ramona should be verified and the risk f property damage assessed in the event of a possible “blow out” if the (probably CMP” pipe should fail. No other action in regards to construction is recommended.

Projects 06 and 07 are low priority projects to increase the capacity of these pipes to be satisfactory for a 100 year storm. No action to change capacity is recommended however, some rock rip rap or other energy dissipation at the outfalls should be considered. .

Project 08 would install ~600’ of pipe from the low point of OST near Las Piedras to Corte Madera Creek. This flow path appears to be adequately addressed at present through a series of pipes and open trench collector structures. The pipe locations and sizes are somewhat different than those depicted in the SDMP.
One home owner contacted indicates that here were no significant problems of flooding or erosion. Pending inputs from other residents, no action is recommended on this project.

Project 09 would increase capacity of the pipes and gutters around the intersection of VV and OST. There are some discrepancies in the SDMP documented sizes for gutters 1020 and 1093 listed as 3” deep and 24” wide are measured at approximately 24” deep and 48” wide. No capacity issues have been observed in the combination of pipes and gutters at this intersection in either the 02/1998 0r 12/2012 storms. Consideration should be given to extending the discharge pipe that currently extends about ½ the distance across the property at the Southwest corner of VV and OST. This discharge point is at the top of an active very active slide that extends some distance down to Los
Ciervos. The discharge generally flow into deep cracks in the soil at or beyond the discharge point. If agreement with property owners for easements could be achieved extending the current pipe or partly as a bioswale onto to more stable areas on or beyond the boundary between 330 OST and 20 Los Ciervos might be considered for safety reasons. No other recommendations

Project 10 would increase gutter sizes on over 1300’ of Joaquin Road. The risk level associated with these gutters when combined with on roadway flows seems to be generally low and there are no documented reports of problems in this area. Recommendation is to take no action on this project.

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
Project 13 would increase the size of pipes #130 and #133 which are significantly undersized due to low slope. There have been no problems observed with these pipes in the past perhaps because any overflow can continue to flow north on
Ramona to the inlets at “Spanish Creek”. An alternative to increasing the pipe size might be to create a new inlet about 50’ south into pipe #132.
Recommendation is to take no action unless problems are documented.

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Attachment 1
Project
01
02 1
04
05
06
07
08
09
11A
14A
15
17
18
21
23
27
29A
30
Total 18
Projects
21 Vista Verde
45 Vista Verde
Property owners affected by projects
Residences affected
144 Carmel
131, 135 Ramona and 120 Carmel
25,35 Las Piedras, 319,333,336,348,354,390 Ramona, 231 Vista Verde 9
400 Ramona 1
10,20,30 Los Ciervos, 280 288 Old Spanish Trail
0, 330 Old Spanish Trail
127,139 Lake 2
205 Old Spanish Trail, 36,44 El Rey, 126 Lake (LTCWD)
1757,179 Los Trancos Circle,1227,1235,1243 Los Trancos Road
1223 Los Trancos Road, 221 Ramona
176, 1184 Bonita 3
55 El Rey, 126 Lake (LTCWD)
108,112,116,124,125,135 Foxwood
1144, 1148 Los Trancos Road
1207, 1215 Los Trancos Road, 108.112 Foxwood
132,144 El Nido, 120 Los Trancos Circle
# Properties
Affected
1
3
1
1
5
2
2
2
6
2
4
4
5
2
2
3
55 Owners affected
1)Carmel and Chiquita were not dedicated to the County as a part of the LTW subdivision but the
County is actively maintaining Carmel
2,3) Affect driveway culverts only
1
2
333

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Attachment 2 Letter to Blue Oaks HOA
April 10, 2020
Joy D. Elliott
Blue Oaks Homeowners Association
Hello Joy:
Thank you for your e-mail of March 1 regarding questions about implementation of the Storm Drainage
Master Plan (SDMP). At the very onset here, the ad hoc committee considering the SDMP wants to reassure you that the District will not move ahead with any parts of this project that might impact the
Blue Oaks Community without the involvement of your association and community members. At the present, the ad hoc committee for the implementation of the SDMP is in the very early stages of grappling with the multiple issues of the interrelationship of the projects, impacts on various parties including Blue Oaks, financing, and what agencies would be best suited to undertake the implementation. We will endeavor to keep your organization fully involved with this effort.
At the present time, there are five distinct outfalls from lands within our District onto Blue Oaks lands.
These are not exactly as shown in Appendix G. The following will summarize the status of our current understanding of the impacts the SDMP on each of these outfall points. Please understand that these are not based on specific work by a registered civil engineer but represent only our understanding of the plan.

C8 Gutter ID 1081
This is the gutter that runs down Los Trancos Road (LTR) from the intersection with Ramona
Road. The implementation of projects 03 & 31 would likely increase the flow in this gutter by an unknown amount and possibly slightly decrease the flow at Outfall #4146 by some small amount.

D7 Outfall ID #4146
As noted above, Projects 03 & 31 could have some impact on the flow at this point. Also,
Project 25 (medium priority) could possibly increase flow in major storm events through improving gutters and driveway culverts upstream of the outfall along LTR. We understand no new flows would be added at this outfall by way of Project 25.

F59 Outfall #4087
The flow at this outfall could be impacted by several projects. Project 29B would divert water from Pipe # 280 to flow down LTR through a combination of pipes and gutters to this out fall. Also, Project 28 and some unnoted gutter and curb improvements near 1148 LTR could add to this flow. Project 27 would improve the incised dirt trench across private property at 1128 LTR to an existing stone lined gutter across parts of 1144 LTR and thence into a 12” PVC pipe which discharges onto Blue Oaks lands. We understand that the property owner at 1148 LTR does not wish to have the channel follow the alignment implied in the current plan drawings. The project would include working with Blue Oaks to implement a detention basin on Blue Oaks lands to moderate peak flows into existing natural runoff channels.

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
G5 OutfallID#4132
Project 30 would improve collection of flows from the North West end of El Nido into an existing collector and then into a new pipe which would carry flows onto Blue Oaks properties instead of having the flows through natural channels to Blue Oaks properties. A detention basing would also be constructed as a part of this project to reduce peak flows.
An alternative to this project would Direct flows South Easterly on El Nido to the intersection with Los Trancos Circle (LTC) and thence down LTC to Outfall #4087

Z58, Z4
This outfall could be impacted by Project 14B which would divert flow from a current pipe across lands at 205 Old Spanish Trail (OST) to flow instead down OST to the Frog Pond through an existing outfall pipe not detailed in the existing plan. (Possibly Pipe #167) This pipe may need to be enlarged once the flow capacity is determined. Project 11C would add a second outfall into the Frog Pond for some additional flows from OST. Note that Project
11B is also proposed to divert flows from OST into the District lake. As the District lake fills there is an overflow pipe at West end of the lake that discharges into an historic overflow basin situated on Blue Oaks property.
As was emphasized at the beginning of this letter the District is in the very early stages of determining an implementation strategy for the SDMP. There are projects that are totally on public rights of way, some totally on private property, and some on a combination of both public and private properties.
Please note as well that any work done on or discharging onto public rights of way must gain approval of the San Mateo County Department of Public Works (DPW). The District has opened a dialog with the
DPW and considers the DPW to be a possible partner or prime mover in any implementation efforts.
Given this very early status, many of the other questions in your inquiry have not yet been considered.
As the committee begins to narrow down the list of projects and establish priorities based upon property risks these very import questions will come into a better focus and the committee will seek answers once a more concise list of executable projects is in hand.
Thank you for your interest and the committee looks forward to working closely with the Blue Oaks
Home Owners Association in implementing any plans. We acknowledge that this letter may serve to only partially answer some of your concerns. It may be helpful to sit together and review what is currently known, perhaps better answer questions where information currently is available and list concisely questions that need to be addressed in the future.
Sincerely,
Stanley R. Gage
For the Storm Drainage Master Plan
Ad hoc Implementation Committee
CC Joe Lococo - San Mateo County Department of Public Works

Page 17 of 21
Attachment 3
Net number of projects
Described
Net after A/B decisions
Projects that affect Blue Oaks
Net BO after A/B
Projects that would need a property owner easement
Projects needing both BO and easement
Remaining projects not affected by BO or easement
Site checked as of 3/30/2014
33
30
11
10
19
2
5
19

Page 18 of 21
Attachment 4 Alternative flow path to projects 23 and 31

Page 19 of 21
From: Cathrine Lemaire < cathrinel@csda.net
>
Date: Wed, Mar 5, 2014 at 9:35 AM
Subject: RE: CSDA Finance Corp: Los Trancos Co Water
I had a conversation with consultant Saul Rosenbaum yesterday afternoon. He apologized for the delay in his response and gave me some information to share with you.
Saul pointed out some key considerations that would make it very difficult, if not impossible, for your district to find financing:
 The fact that the district is considering a dissolution and that LAFCo has recommended such action
 The proposal includes projects located on private property, which is problematic for taxexempt bonds

Operating costs such as staff salaries cannot be included in such a financing

Most importantly, there is nothing in the district’s financials that indicate an ability to repay a loan
Saul’s quick analysis showed that a $3.5MM loan for 30 years at an interest rate of approximately 6% would mean an annual debt service of $240,000. Since the district’s total budget is $290,000, about 82% of the budget would have to go toward paying off the debt. It is simply not affordable.
It is Saul’s opinion that Los Trancos County Water District would not be able to qualify for financing for the proposed projects outlined in the master plan.
I hope this information is helpful. Please let me know if you have specific questions about the consultant’s response.
Best regards,
Cathrine

Page 20 of 21
1.
Gutter/Ditch on east side of VV south of OST is listed at 0.25’ deep. Minimum measured depth is 1.5’.
2.
Pipe 281 near 1207 LTR is shown on Google Earth but not detailed in Pipes Appendix data
3.
Pipe 279 is detailed in appendix as 15” pipe with no risk but is suggested as a part of Proj
02 to repair a deeply incised open ditch down a hillside. This pipe is apparently referenced in report intro as work already undertaken.
4.
Gutter/Ditch between 1008 and 1038 LTR is not shown in any of the appendix data or
Google Earth or as an outfall onto BO lands. This is a very significant ditch apparently carries significant flows (as judged by erosion) and is very evident to any casual observation.
5.
Pipe 129 is shown as terminating under the structure at 333 Ramona. In fact this pipe runs easterly for approximately ½ the distance from the road edge to the structure, turns Northerly for approximately 75’ and then turns easterly again for approximately
150’ terminating about 3’ before the access driveway to 317/319 Ramona. Flow is then intercepted before the driveway along with other surface flows goes under the driveway into a surface trench about 4’wide by 2’ deep for ~30’ and then is intercepted again into a 12”’ pipe and flows >100’ to Los Trancos Creek
6.
Pipes 244, 245, 246, 247, 140, and 141; Project 08. Pipes 244 and 246 are not properly located with respect to the structure at 10 Los Ciervos. Pipe 246 terminates in a large catch basin about 30’ from the north west corner of the long structure on 10 los Ciervos and pipe 244 is actually 18” diameter running ~80’ due west and terminates in a ditch running downhill for an unknown distance toward Corte Madera Creek where it is intercepted by a 30” CMP running an unknown distance to the Creek. There is a properly locted inlet at the approximate location of the depicted intersection of pipes 246/247.
The pipe section 247/245 is continuous uphill from inlet 4128. Outlet 4149 is not apparent at the site. Pipe 245 appears to run approximately 90’ further north east uphill from the terminus shown. Pipe 141 apparently runs about 40’ further southwest downhill than depicted on Google maps.
7.
There appears to be a missing element or elements in the complex of pipes 207,208, and 209 and catch basins 3034, 3035, 3036 and 3039. There are no outfalls shown and there is alleged to be a culvert pipe that runs from either or both 3034 and 3035 downhill and under driveways and a garage and eventually into Los Trancos Creek. The capacity of this part of the system is critical and failure due to flow in excess of capacity, clogging, and/or failures of the CMP are well documented.

Page 21 of 21
1.
Projects 03 and 31 combine to divert flows from the intersection of Foxwood and LTR to eventually flow down existing gutters past the intersection with Ramona Rd thence into drainages BO34 &35. A safer alternative would possibly be to construct the gutters from the end of Proj 31 to channel flow into the existing large ditch that flows onto BO 32 /
BO33 and thence into BO 35 See #4 above under oversights). (Increased) Flows from this discharge should be moderated by construction of a detention basin on BO lands.
Culverts under the BO emergency access road should be reviewed to insure adequate capacity to handle flows.
2.
As alternatively to #1, the plan gives no explanation for not considering use of and improvements of existing private gutters on 1091 LTR and 113/115 Foxwood as well as on Foxwood Rd. Even with Proj 31, the downslope runoff from these properties may be sufficient to continue the reported flooding problems on the lowest properties (e.g. 135
Foxwood and 152 Ramona in this basin located above Ramona Road).
3.
The plan does not explicitly account for reported downslope flows from the alley that runs between 103 and 111 Carmel and as far back as 146/147 Carmel. If this is from unconstrained flows on upper Carmel, the rolled curb suggested in Project 02 should at least partially correct this. Some of this problem, however may be downslope flows from properties located north of Carmel on Ramona Road.
4.
The owner of 1148 LTR reports sheeting runoff from LTC during heavy rains is damaging his property. Consideration should be given to a curb and repair of a short area of probably inadequate gutter size along the northwesterly side of 1152 LTR.
5.
Pipelines #239 and 240 which discharge as outfall #4146 are modestly undersized for the predicted 10 and 100 yr flows. These were constructed as part of the Los Trancos
County Water District Demonstration Culvert improvements program. These pipes reportedly have presented ongoing maintenance problems for the county DPW.
6.
The routing depicted for pipe #120 could suggest the possibility of significant property damage if the structural integrity of this culver is breached. This routing should be verified if possible and consideration given to rerouting to be within the road ROW.