Recreating San Francisco: Real Life Aside, October 1, 2009

[ldvger]

Well, I made a discovery this evening that has kinda knocked the wind from my sails.  It's an OCD thing actually and I'm trying hard to get my brain to let go of it and I think I am succeeding, just not sure quite yet.

It came about like this.  I was going to start plopping water in Stafford Lake tonite, building first the earthen dam and then the lake behind it. 

Ok, NEVERMIND!!!!  Sorry to turn psycho, but I just figured out my error.  I'll continue my little mini-story anyway, just to amuse whoever may be amused by it.

So I know the dam is 71 feet high, so the first thing I did was check terrain elevation between the lower end of where the dam will be and the surface of the lake.  I was horribly dismayed to find a difference in elevation of only about 20 feet.  Then I checked the surface of the lake and found it was about 80 feet too low, according to my RL topo maps.  The 200 foot contour line runs all around the lake and there is a notation on the topo that the spillway elevation is 199 feet.  Well, if sea level is 250 in game, then 250+ 199= 449, right?  Yet when I queried the flat terrain of the area of the lake, it told me 351 or so.  That's almost 100 feet off!  I totally freaked out.  After all the care I took to scale everything, to find my z axis was compressed almost 100 feet just bummed me out big time (for those not familiar with graphing axises (axi?), the x axis is horizontal north/south, the y axis is horizontal east/west, and the z axis is vertical up/down).  So then I was on a mission to figure out if I could fix it.

Well, anyone who works with custom content has probably already figured out my error.  The game doesn't use feet and inches, it uses meters.  Being an American, I have to keep a cheat sheet next to me to convert meters to feet and I completely forgot to do that.  Just as I started to write a long sob story, the light bulb went off in my head and I quickly used my calculator and found that the z axis of my game is about as close to right on as it can get. 

Panic attack averted and an hour's reading searching tutorials for advice, while not wasted ever, was for the time being, er, unnecessary.  I feel silly...and stupid. 

Back to the game.  Maybe I will have some pics of the lake tomorrow...and the dam.

Lora/LD

[projectadam]

Lora,

Do not feel bad, if NASA can make the same mistake with the Climate Orbiter on September 23, 1999, you should not feel too bad about making the same mistake

[u.mueller]

First of all, Lora, I admire your striving for perfection and the use of professional programs to reach your goal! Second, as my fore-poster said, never mind your error, it happened before and it happened where money depended on it!

One example springs to mind: back in 2002, a company released an addon for MS Train Simulator, where feet have been mistakingly used in a simulator that uses meters, leading to mountains (and thus trackage grades) being 1.5 times as steep as they should have been. Guess: The addon flopped completely!

I'd simply book it under "lessons learnt" and keep on going!

[ldvger]

Thank you both for your kind words, I really appreciate it.  My RL has been fraught with challenges these past two weeks and I've been feeling really beaten down, so words of kindness and encouragement are very, very welcome. 

I know we all make stupid/silly mistakes and that I am not immune to them.  But like everyone else who finds out how dumb they were for a while, it's a little embarrassing.  I know the translation between metric and foot/inches is a common problem for US users and I am usually very careful...just went brain dead tonite and that resulted in a freak-out. 

All better now and if it wasn't so late at night (1:09 am my time), I'd go back into the game and build away.  But, I have learned to ignore these late night wine-induced impulses, for the most part, so I think instead I will go change into jammies and brush my teeth and...go to bed (what a concept, sleep before 2 am!).

Lora/LD

[Albus of Garaway]

I know how you feel about sleeping. I get strange impulses to play SC4 and visit SC4D at, say, midnight or something ridiculous like that. It's actually quite frustrating at times...!

-Jason

[Battlecat]

It happens to all of us, and it's always a heart stopper when you realize you've made an error with units.  I have to be extra careful at work since we have a wide variety of legal plans that I have to manipulate that are scaled in meters, feet and even chains (20 or 30 meters depending on which kind of chain they use!).  I've had some real panic attacks from trying to double check an old subdivision only to discover I used the wrong units! 

Glad you managed to catch it before you really started in to the terraforming to fix it!  Anyhow, I'm really enjoying how you're approaching this, you've really put Autocad to excellent use!  I like your idea of bringing the game map into autocad before you start developing, it'll really help you line things up nicely! 

I'll be interested to see how you handle your earthen dam, I'm working on one in my diary as well, and it's certainly an interesting visual challenge.  Keep up the great work, I'm looking forward to the first in game shots! 

[ldvger]

Beginning of Major Diversion #1: Novato Creek Dam

(preparing everyone for many more of these to appear in the future)

Jason, I think SC4 draws a lot of us sleep disorder folks to it.  I myself am a chronic insomniac and have been my entire life, from birth forward.  A few years ago when my baby sister died at the age of 44, my remaining sister and I flew home to Santa Barbara to gather with the family to mourn our loss.  My dad braved the perils of the Los Angeles freeway system to pick us up at LAX and on the long sad drive north, we reminised about Kim and I shared my memory of the night she was almost born on my birthday in May of 1960.  Our family had just moved to California from Michigan and my dad was working in LA while we were living in La Jolla.  My uncle (my mom's brother) had just gotten out of the Navy and was staying with us during the week while dad was away, so that if mom went into labor he could drive her to the hosital.  Mom went into false labor in the early morning hours of my 6th birthday and I heard everyone up and moving around, so I got out of bed to see what was happening.  If I remember recounting this correctly, I told my dad and sis "I was awake, so I got up".  At that point my dad interuppted me and said "You were ALWAYS awake!".  So...sleeping has been a lifelong challenge for me.  For me the problem is falling asleep, as I have a lot of trouble turning my brain off.  Once I fall asleep I sleep pretty good for about 3-4 hours, but then I am off and on asleep and awake for another 3-4 hours.  I imagine there are drugs I could take that would help, but being both unemployed and uninsured, I use wine. 

Battlecat, you must be in the land surveying business, or engineering.  I am familiar with chain measurements and even worked once as a "chainman" on a survey party, holding the "smart end" of the chain.  When I first moved to Washington State in 1976 I was living with a civil engineer who was also a licensed surveyor.  He was short a chainman for a small job he was assigned to do, so he enlisted me to help out.  I had just started my career in architectural drafting, so I enjoyed the day's work, even though it was raining and windy and cold and the parcel we surveyed was covered in blackberries and mud.  Always fun to learn new stuff. 

As for converting feet/inches to metric, I haven't had to do so for quite some time, which is why I made myself a little cheat sheet to keep handy while I play.  Years ago one of my employers landed a client in Japan who wanted to buy all the materials for a number of houses here in the USA then ship each house seperatly over to Japan in a container.  I was assigned the job of converting all the American measurements to metric so the carpenters in Japan could read the dimensions on the drawings.  We did about 12 houses for this client, so I got pretty good at converting, but like any special skill, if you stop using it, you lose it. 

And as for the earthen dam (the Novato Creek Dam) that creates Stafford Lake, I was just going to use the level tool for that.  Ennedi just showed me that I could use this tool across sloped faces to create a uniform slope and jeronij has a method using roads that I've found works pretty good, too.  So that's my plan: create a uniform slope on the downstream side then create a one tile width level at the top, and probably put a road on it, then another, less tall, uniform slope on the lakeside of the dam.  Nothing fancy, really.  The biggest challenge will be the spillway.  I think I'll see if I can't find some very simple concrete retaining walls and then make a channel running down the north side of the dam and fill it full of water turbulence.  Rather than building a bridge over the spillway, I think I'll use a culvert, maybe two.  Think that'll work?

Off to buy chili fixings and I'll be meeting with my knitting group this evening, so I may not get around to SC tonite. 

Later!

Lora/LD

[Battlecat]

I work with Geographical Information Systems (GIS) for a small community in BC actually.  GIS is effectively the software used to create digital versions of those topographic maps you're working with.  But of course, all our data is obtained from older legal surveys, some over 100 years old, which is where the chains come in. 

Your plan for that earthen dam sounds pretty good.  I used roads to smooth the face of the dam I'm working on.  I think culverts should work fine for the spillway outlet assuming you can find some with a good shape.  Perhaps there are some box culvert models floating around (large square culverts).  I wouldn't recommend the RRP culverts though, they're not quite right for a large dam spillway but I'm sure there must be something floating around that would work although i haven't found it yet. 

As for the actual function of the spillway, the one thing to consider is that on an average day, there shouldn't be water flowing down it.  The spillway of a dam represents the maximum level of the reservoir and only fills with water if significant rainfall or rapid snow melt causes that level to be exceeded.  As such, you could probably create an effective visual with just a dry concrete surface, which visually speaking is quite likely for the San Francisco area.  Spillways are also designed to dampen out the force of the water dropping that distance to prevent dangerous erosion downstream from the dam. 

The water that's used for power usually emerges from several large culverts at the base of the dam.  Granted, a large number of the dams in California are water supply related, not power, so the generation facilities might not be present.  Either way though, environmental standards require a certain quantity of water to be released through the dam into the river below, regardless of human power and water needs.  That quantity varies depending on location and history (The Colorado River vanishes before it reaches the ocean at some times of year).

Anyhow, here I'm rambling on.  That's just my take on the subject, hope it helps you along.  I'll be interested to see what kind of approach you wind up taking!

[ldvger]

Ongoing Major Diversion #1: Novato Creek Dam

Battlecat says:

I think culverts should work fine for the spillway outlet assuming you can find some with a good shape.  Perhaps there are some box culvert models floating around (large square culverts).  I wouldn't recommend the RRP culverts though, they're not quite right for a large dam spillway but I'm sure there must be something floating around that would work although i haven't found it yet.

Well, this is really not a very large dam at 71' in height and 650' in width.  The spillway itself doesn't appear to be more than about 8' wide in RL, if that.  So, I was planning on using RRP culverts, one, maybe two. 

Visiting Google Earth again just now, I was able to snap a couple of pics with scales to show the actual spillway:



This gives a lot of information in one picture.  See the road next to the spillway?  That's probably about 25 feet wide, shoulder to shoulder.  The spillway is wider, but not by much.  There is a scale in the lower left hand corner of the pic that helps determine the width of the top of the spillway.  Also note there are no (visible) flood control mechanisms.  It appears that if the lake level rises, the spillway releases water unchecked into the creek below.  I know from reading/researching this dam that spillway elevation is 199' while average lake elevation is about 2' below that at 189'. 



This shows the lower end of the spillway and you can see it narrows quite a bit as well as deepens.  I am assuming the horizontal bars we see between the walls of the spillway are something like 6" steel pipes acting as tie rods between pins set into the earthen walls of the spillway on either side, to keep the concrete spillway walls from spreading outwards from the force of the water when it runs down the spillway during flood conditions.  Again from reading/ research, I know this dam was raised 7' in 1971 and it could be these ties rods were added at that time.  If you look closely at the first pic you can see where the second, later, addition to the spillway was made, but not certain it shows up in this pic. 



Swinging around to a new compass point, we get a view of the dam itself.  It's really not that big, as the scale at the bottom left helps to see.  The spillway is on the right.  And, I think, but am not positive, that the large building we see is a water treatment plant, as this dam's primary purpose is to provide drinking water to the city of Novato.  I don't think it plays any role at all in either flood control or power generation. 



This is what I think is a fairly inclusive pic of the entire waterworks below the dam.  It also shows the transition from built spillway back to natural creek that takes place under the road to the water plant.  Looks like this road washed out over the spillway at one time, as it's surface color is very different from the rest of the road.  Then again, maybe the road is asphalt and the bridge over the spillway concrete.  Any SF residents want to take the family on a picnic to Stafford Lake Park and check it out for me?  And while I'm at it, anyone wanna BAT and LOT this water treatment plant for me? 



Lastly, this is a pic of the bridge over the spillway to natural stream transition.  I know from my reading/research that there were worries when the dam was built in 1951 that it would destory the creek below and important watershed areas, which is why flood control was not really included as a function of the dam.  To my best understanding, this creek still floods pretty much unchecked during heavy rain.  There really isn't any significant snow in the surrounding hills, so snowmelt really isn't an issue.  I have traced this creek in Google Earth from it's outlet in San Pablo Bay to the spillway and see no evidence of flood erosion anywhere once it returns to being a natural creek.  In short, this is California and they just don't have the rainfall issues we have in the Pacific Northwest.  This creek probably runs at a mere trickle most of the year and at full spate during flood may do some minor erosion, but there are houses and roads built right up to the edges of it's high water marks, so I don;t think anyone sees it as a flood concern.  It's a creek, not a river. 

As for the actual function of the spillway, the one thing to consider is that on an average day, there shouldn't be water flowing down it.  The spillway of a dam represents the maximum level of the reservoir and only fills with water if significant rainfall or rapid snow melt causes that level to be exceeded.  As such, you could probably create an effective visual with just a dry concrete surface, which visually speaking is quite likely for the San Francisco area.  Spillways are also designed to dampen out the force of the water dropping that distance to prevent dangerous erosion downstream from the dam.

Points well taken.  So maybe the horizontal pipes we see in the spillway are designed to slow the force of water in the spillway rather than hold the spillway together?  Maybe they do both?  Maybe they act as artificial rapids?  They do appear to be at various heights along the walls of the spillway and any obstacle rushing water meets will slow it down.  Must be fascinating to be an engineer who designs such a structure...

Granted, a large number of the dams in California are water supply related, not power, so the generation facilities might not be present.  Either way though, environmental standards require a certain quantity of water to be released through the dam into the river below, regardless of human power and water needs.  That quantity varies depending on location and history (The Colorado River vanishes before it reaches the ocean at some times of year).

Well in that case, there must be another set of release mechanisms built into the base of the dam, as I see no way of lowering the height of the spillway itself, mechanically.  Which doesn't mean such a way doesn't exist, just that it seems a bit improbably to me as being practical. 

This all makes me wish I lived in the SF area and had a car, so I could drive up and see for myself what is what.  Maybe I will email the folks at the Marin Country Water District and see if they will tell me more about this structure and how it works.  Can't hurt, although I doubt they will answer me.  Who knows?

Anyhow, here I'm rambling on.

I like your rambling, I hope you come back and do more, you gave me some great ideas.  In case you haven't noticed, I tend to ramble a bit myself (ya think???). 

Lora/LD

[Battlecat]

Glad you found it handy!  Those shots are very useful, there certainly is a lot of information in them.

I think your first instinct about those crossbeams is correct, although I suspect they're also present to help keep the earth part of the dam from breaking the concrete in case of an earthquake.  If you look carefully at the shadows in the second shot, there are clear signs that the actual beams are elevated above the bottom of the spillway. 

There is one other interesting quirk about aerial imagery that we can take advantage of.  To a certain extent aerial photos actually let us look at the side of certain structures, since they are only directly overhead at a single point.  This let's us see something interesting about the design of this dam on the photos you took:


The red circle is around what looks to me like rapids caused by water flow.  It's possible that the upper dam has a small release culvert hidden in the shadows there.  In the orange circle there is a vertical structure that looks like a set of gates to me, they appear to be closed and the dry channel below the gates bears that out.  So the question is, where does the water go from here? 

One possible answer is indicated by the yellow circle.  The shadowy area between the spillway and the road suggests the presence of a lower area.  I would hypothesize there is a small constructed natural stream in that space, which is probably set up to only take normal flows of water.  During a major flood event, the excess water could be diverted through the spillway which does appear . 

This theory is aided by your topographic map posted earlier.


You can see the natural stream course is quite close to the road before swinging down to where the spillway flows into the natural watercourse (just beside the hook shaped access road).  With all the tree cover, it's hard to see exactly how the stream re-connects with the spillway watercourse, probably through a culvert under the road somewhere down there.  However, for the purposes of SC4, it probably doesn't matter since the natural stream will be hidden under tree cover! 

Having seen the google earth shots, I don't think there is a separate release mechanism for this dam, it appears the spillway system is designed to serve both purposes.  Either way, I'd over estimated the scale of this dam.  I think the RRP culverts would work better for the purposes of this simulation than I thought here. 

Also, I can't help but notice that the surface of the dam looks like it's covered in grass and small shrubs.  They would provide sufficient slope stabilization in regions with low rainfall.  In the Pacific Northwest and British Columbia, many earthen dams are coated in coarse rock probably to help prevent frost and ice from damaging the earthen surface. 

Edit: Of course, in trying to preview, I accidently posted! 

[MrWacko]

Battlecat, Lora:

For two folks who've probably never been to Stafford lake, you guys managed to figure it out almost to a tee. The dam itself is indeed completely for water purposes for the City of Novato, but being small and having only a few feeder creeks, is most certainly not the main source. The little creek in the shadow of the road is indeed, the primary water outlet for the dam, and when it reaches flood conditions, the spillway takes over. The dam is also reasonably covered in grasses. Again, no serious flood control is needed since average rainfall is around 35"

I don't remember any time in the past two years where that particular creek had any significant flood issues. While some creeks do indeed qualify as flood concerns, this one isn't. The actual dam generally is sufficient for flood control, so when the big storms hit it mitigates the creek.

Flood control is needed, though, for most rivers and creeks. Almost all of that rain comes between November and March. Infrequently you'll hear news stories during the winter about the North Bay area flooding, since it occasionally does get really nasty.

As for the road, it's concrete. As mentioned, the creek rarely if ever floods. No picture, just my memory of driving over it a few hundred times. I grew up in West Marin .

Edit: Hmmm, I seem to have made the same mistake as battlecat... Silly preview button not being where I want it to be...

[ldvger]

Ongoing Major Diversion #1: Novato Creek Dam

Well, excellent!  You are both turning out to be wonderful resources for me, thank you very much!

Battlecat says:

I think your first instinct about those crossbeams is correct, although I suspect they're also present to help keep the earth part of the dam from breaking the concrete in case of an earthquake.  If you look carefully at the shadows in the second shot, there are clear signs that the actual beams are elevated above the bottom of the spillway. 

When I first viewed them yesterday, I surmised there were several "layers" of cross beams across the spillway, set at different heights above the base of the spillway, but looking closer today (and your having pointed it out to me), I think you are correct, those are shadows cast by the beams and the beams are all at a relatively uniform height.  Good eye!  And I completely spaced the entire earthquake issue and how lateral movement of the dam could collapse the walls of the spillway, so yes, very likely explanation.  If the cross beams are tied into pins embedded in the dam and hill below the road, the spillway would then move as a unit with the dam during a quake.  Jeez, I really shoulda been an engineer, must be so much fun to design structures like this, taking all the gazillion little variables into consideration. 

The red circle is around what looks to me like rapids caused by water flow.  It's possible that the upper dam has a small release culvert hidden in the shadows there.  In the orange circle there is a vertical structure that looks like a set of gates to me, they appear to be closed and the dry channel below the gates bears that out.

Re: the red circle: or maybe debris that has accumulated from when the gates under the top of the spillway are opened?  There is plant growth in that section, too.  To my eye, this upper part of the spillway appears now to be dry in this picture.  When I originally viewed it, I also thought the base of this part of the spillway was raised above that below it and that the structure you have circled in orange was the top of the original spillway from before the dam was raised.  In fact, this probably is the original spillway structure but what you have seen as gates I took to be a little concrete dam and the lighter colored area in the center I saw as a little waterfall spilling a trickle of water from the newer upper spillway to the original lower spillway.  But now I think you are once again correct in finding those to be moveable gates which are currently closed.  I also now think the base of the spillway is the same elevation on either side of the gates, now.  Shadows can be tricky!  And yes, where was I thinking the water I thought was trickling over the face of what I thought was a little concrete dam went, because very obviously the lower spillway is dry.  I guess I just didn't think about it at all.  Hey, it's California, it's summer (June when this image was captured), so the water just evaporated between the upper and lower spillway!  Not! 

One possible answer is indicated by the yellow circle.  The shadowy area between the spillway and the road suggests the presence of a lower area.  I would hypothesize there is a small constructed natural stream in that space, which is probably set up to only take normal flows of water.

I think you are right and MrWacko backs you up from his actual observations, but now the question is, how does the water get from the lake, which is at a higher elevation, down to the beginning of the "natural" stream?  Looking closely at the picture again, it appears that there is water in the natural steam here in June and it doesn't appear to be running at any speed.  If the water is diverted from the lake to the beginning of the natural stream, the change in elevation would cause turbulence in the stream, would it not?  Unless it was metered somehow, that's a thought.  In fact, that's probably the answer to the question.  Otherwise the natural stream, being so close to the road, would cut into and erode the roadbed above it.  Yeah, that's the ticket!  This semi-constant release of water from the dam into a natural stream was probably done to maintain the important stream ecosystems further down stream and especially out on the salt marshes it feeds when it hits San Pablo Bay.  Sheesh!  So many things to keep track of!  And here I thought it was just a simple earthen dam with a concrete spillway!  Who'd of thought that folks all the way back in 1951 would be worrying about preserving natural water systems?  But they were, because I remember reading about that in the history of the dam and area.  And this was thier solution.  Simple and elegant at the same time, like all good solutions are. 

Also, I can't help but notice that the surface of the dam looks like it's covered in grass and small shrubs.  They would provide sufficient slope stabilization in regions with low rainfall.

You probably are familiar with the term "angle of repose" but for those who are not, it's used to describe how various soils and/or mixtures of soils are naturally stable at certain angles.  Sand has the least angle of repose, which from my soil science classes years ago I seem to recall is 45 degrees.  I won't go into what affects the angle of repose, it's very complicated, but knowing that much of the soils in this area are sandy due to all the heavily eroded sandstone in the mountains and hills, I now can understand why the slope of this dam appears to be much shallower than I had expected it to be.  We have heavy clayey soils here in the NW and thier angle of repose is much higher, so our earthen dams are steeper and, as Battlecat points out because we have much heavier rainfall, they are more prone to serious erosion, so that simple plants life is not enough to keep the face stable and in place.  But, that also brings up another question.  The lakeside surface of the top of the dam appears to be, if not earth, then treated with maybe shot crete.  It doesn't really look to be atcual concrete and we have to remember what we are seeing of it is actually the newer portion that was added in 1971.  I also noticed the dam face on the downstream side is much steeper, where it's height was increased.  This puppy is going to be tricky to render in my game, that's for sure.  Lots of fine, detailed terraforming indeed. 

But, with all these new thoughts to think about, I'm going to go back to Google Earth and see if maybe some of my remaining questions can be answered.  I may edit this post with new pics again later, but in the meantime, you sure I can't talk you into taking the family for a picnic this weekend, MrWacko?  Sure would be nice to have some "boots on the ground" to check things out...

Lora/LD

[MrWacko]

But, with all these new thoughts to think about, I'm going to go back to Google Earth and see if maybe some of my remaining questions can be answered.  I may edit this post with new pics again later, but in the meantime, you sure I can't talk you into taking the family for a picnic this weekend, MrWacko?  Sure would be nice to have some "boots on the ground" to check things out...

Lora/LD

As much as it'd be helpful, I can't. I don't live in Marin anymore. I'm at school at UCSC, so it's a good 2 hours north to Marin. Don't worry, I've got confidence in my memory. 18 years in a county does leave you with lots of memories, after all.

Of course, when I do get to go up to Marin, or anywhere else your current project happens to be, I'll gladly send pictures. I go too and fro enough, that's for sure.

[Battlecat]

Good point, that could indeed be debris in that area, it's really hard to tell with all those shadows.  They are the bane of interpreting aerial photography! 

There are several things that could be done in that stream bed to reduce the erosive power.  Heavier rocks along the edge of road bed (riprap) will prevent significant erosion in that area.  The natural stream bed could also be engineered with switchbacks and pools to dampen the power of the stream and reduce the slope. 

As for the grey side of the dam, it's possible the lake isn't at it's highest point in the photo.  It's hard to tell because of the angle of the photo but the lower left corner indicates that the photo was taken in June 2007. 

In the aerial images, we are looking at the downslope side of the main spillway gate, as opposed to the top on the side indicated by the red arrow.  Because of that odd angle, we can't actually see how far up the spillway gate the water is, it's being tricky making it look like the water is right at the top.  However, the lower of the two lines marked by orange dots looks like a high water mark to me.  I think the upper one marks the inner edge of the top of the dam. 



Over the course of the summer, the level of the lake will drop, leaving bare soil/rock around the edge.  They probably used heavier rock or possibly even shotcrete as you mentioned on the lake side of the dam to prevent erosion from waves.  Plants wouldn't be able to survive the constant variation in water supply, particularly since the height of this lake appears to be quite variable from year to year. 

In fact, you could probably check other parts of the lake to see if there are other places with the high water mark and bare soil, most dam lakes have a strip of bare soil around the edge because of the variation in lake level over the year.  Also, I gather there is a recreation area along the lake, you could check the placement of any dock or boat launch structures, they are often built on dam lakes so they are usable any time of the year. 

In the end, the limitations of SC4 are going to prevent the replication of a lot of these structures, but hopefully you can make it as close as possible!  You've certainly given my mind a workout today, I do get a great deal of enjoyment out of interpreting aerial photos! 

Edit: One more thing, I discovered by accident that google maps streetview actually has data in the Stafford Lake Area.  Not quite as good as being on the ground, but it might help.  It might take a few minutes to load, use any web browse!  If you haven't used it before, you just use the arrows to move along the road.  Have fun! 

[ldvger]

Ongoing Major Diversion #1: Novato Creek Dam

Well, I think the three of us have chased off all the other folks who were viewing this MD with our obsessing over this dam structure.  Be that as it may, I'm still obsessing and have some new pics to post that put forth a new theory of how this dam works.  But first a little story to share.

I learned the bare bones of manual drafting over Thanksgiving weekend of 1976.  My boyfriend, Bob, had flown east to spend the holiday with his parents, they having sent him a round trip plane ticket as we were both too broke to pay for same ourselves.  We had been living together for all of 2 months (even though we had a relationship stretching back nearly 4 years) and I was extremely miffed that I was not included in the family holiday.  Bob and I had a huge fight about it...I felt he should decline the invite because I was not included (such is the wounded pride of a 22 year old girl in love).  Bob just laughed at me and flew off Wednesday, leaving me alone in a strange land with no friends to spend my first Thanksgiving Day ever away from my family.  Bob had a degree in civil engineering, was an excellent freehand and technical artist and had a drafting board set up in the spare bedroom of the beachfront cabin we had rented for the off-season.  I had taken drafting in junior high school but transfered out after the first day because I was the only girl in the class and all those boys intimidated me.  Bob had gotten a job as a drafter for a log home kit company and I used to sit and watch him draw on the drafting board.  When he left me alone for the holiday weekend, I thought to myself "F*** him, I'll show him!".  I worked at the time as a hostess at a seaside restaraunt and every night after work I'd go across the street, buy myself a six pack of beer, then go home and teach myself drafting.  Bob had a shelf full of engineering books next to the drafting board and one was titled "Beginning Drafting".  I sat down Wednesday night with my cold beer and opened the book to page 1, chapter one, and started learning how to draft.  It was all just learning the tools and going through various exercises, pretty boring stuff, but I took it very seriously.  The book told me "don't erase, redraw!" so I took the advice to heart and went through a LOT of paper.  By Saturday I felt confident in starting chapter 2, but it was some exploded view of a tool, so I closed the book and started to design my first house, instead.  By Sunday night I had a floor plan and an elevation, which I proudly showed to Bob when he returned Monday.  He got this well-known (to me, anyway) faraway look in his eyes as he looked at my work, stroking his wispy excuse of a mustache (which he was growing for me, cuz I love the way they feel when kissing) and told me my work was very good, then he proceeded to critic my errors.  I welcomed his critic and after that we started working together in my adventure into drafting.  He built me a drafting board out of 2x4's and a hollow core door that we placed behind the couch in the living room facing the fireplace and gave me ever harder exercises to practice on.  Then one night he came home from work and told me he had gotten me a job drafting for the same company he worked for, as one of thier other drafters had quit that day.  Our second big fight ensued.  To me, my drafting was like a hobby, like knitting, and it had never crossed my mind to attempt to make money at it.  I knew NOTHING about construction or codes.  Bob promised me he'd walk me through it and help me whenever I needed help, so I finally agreed to give it a go.  Little did I know, I was launching a new career.  My first project was a nightmare for everyone, because Bob's promised help never really materialized and we had fights at home and at the office.  I kept asking what's this, why should I do that and he would say just draw it.  But that's the way my brain works...I have to understand the underlying reasons.  I'm not a good little robot that just accepts commands and follows orders.  Well, I got paid more money than I had ever made in my short life for that project, so I finally quit my other job and became a full-time architectural drafter.  I was on my way forward in a completely new direction and believe me, I never looked back. 

This is just a story to say why I am still working on figuring out how this dam works.  I can't help it, the hook is set in my brain and I am being pulled along until I either finally figure it out or someone, like Battlecat and MrWacko, help me.  If anyone else is still reading this MD, there will come a time in the future when your particular area of professional expertise will contibute to helping to remove the hook from my brain, so be patient with me.  Being OCD is both a gift and a curse, and right now it's more of a curse than a gift.  I know folks are anxious to see some development and a lot less techno talk, but I think we are closing in on answers and I am becoming antsy to start building as more and more of the secrets of this damn dam are being revealed. 

MrWacko says:

As much as it'd be helpful, I can't. I don't live in Marin anymore. I'm at school at UCSC, so it's a good 2 hours north to Marin. Don't worry, I've got confidence in my memory. 18 years in a county does leave you with lots of memories, after all.

Of course, when I do get to go up to Marin, or anywhere else your current project happens to be, I'll gladly send pictures. I go too and fro enough, that's for sure.

I hope you know I was teasing/joking.  However, if you ever DO have the chance to check stuff out for me, give me a few days warning and I'll send you a list. 

Battlecat, I think my new theory and the following pics will maybe either clear up some of the conjecture on both our parts or else horribly confuse us both.   

One of my biggest questions is how does water get from the lake to the "natural" stream.  I think I may have found the answer.  Look at this pic:



I think I see a small intake culvert to the immediate left of the upper spillway.  I also think I see an outlet at the right of the retaining wall:



Hmm?  Ya think?  Maybe?  Am I on to something here?

Ok, now look at this:



Look at the bottom of the area below what we have determined are the original spillways gates.  I don't know about you, but I think I see water there...and turbulence appropriate to a small pipe draining a lot of water pressure at the intake point, which would be somewhere below the surface of the lake and behind the dam.  This picture also has some other interesting things to think about.  The new spillway seems to be much lower in elevation than the lower gates and the ground level between them does seem to be roughly equal.  The area between them does appear to be dry and filled with rubble/debris/flora.  Also note that what *I* took to be shadow cast by the roadside of the spillway wall is now seen to most likely be water running down the roadside edge of the spillway:



My computer is showing all the usual symptoms of fatigue, so I'm going to post this now (already made a backup) and then come back and edit to continue.  Sorry for the delay, I'll be back shortly.

Ok, back now and things seem to be fine after a restart.  Fingers crossed!

So, to explain the imagery shown above, I think there is an opportunity for the natural stream to flow down into the spillway immediately after exiting what I believe to be the outflow that creates the natural stream.  The spillway drops at much greater slope than the natural stream does but they evendtually reach the same or similar elevation (pics to folllow). 

So my new theory is this.  There is a diverting pipe that intakes water from the top of the spillway and diverts it around the roadside of the top of the spillway to exit below the originally spillway as a "natural" stream.  Look at the pics and you will see a "wing" built in the downstream direction of the spillway to the downstream side of the original spillway gates and to the roadside of the spillway.  I believe now that this wing is intended to channel the natural stream into a prepared bed that is just slightly higher than the bottom of the spillway itself and to spill over into the spillway once in a while.  Close up pics I haven't posted but which the pics I HAVE posted sorta show, bear this out, I think.  So the natural stream acts in essence as the primary spillway for the dam.  If the natural stream begins to run to high/too fast, it spills over into the contructed concrete spillway just below the gates.  We can see there is a difference in elevation between the bed of the natural stream (which is higher) than the base of the spillway just downstream of the gates, otherwise the water entering the lower spillway from the surmised underground pipe from the lake would  not run down the spillway but would instead enter the natural stream. 

At the face of the spillway gates, this is what I think is happening:



And with this, I am thinking we have figured things out.  I am often wrong and have no experience with translating aerial photos, so battlecat, I welcome your critic of my new theory...and any alternatives you may have to present. 

Getting late and my wine is beginning to befuudle my brain, so I will leave things as they are, although I have more pics.  They don;t add substantially to my new theory except to point out a built and tall concrete diverter wall just below the gates on the side of the spillway away from the road.  I at first thought it was a gap in shadows, but after closer zooms, I now think it is a built structure. 

Lora/LD

[Battlecat]

The more I look at those shots, the more I have to agree.  The space between the lake and the concrete lower gate hasn't been used in a long time and that does appear to be dirt and plant growth rather than water flow.  It's quite likely that large gate like structure is only intended to be used in extreme emergencies, which would be fairly rare on this particular lake.  Your theory about the two culvert/drainage pipes has a great deal of merit, although when it comes to shadows I'm always worried about interpreting something that's not actually there!  But I think you're pretty close to being correct on this design simply because there really isn't any other route for the water to take.   

We know from MrWacko's observations that there is a natural stream there, separate from the spillway.  That water has to come from somewhere, and there isn't any other obvious way to get the water from the lake to the natural stream.  It certainly is possible that there is a small quantity of water in the spillway by default, but that's another hard one to call for sure since there is also a shadow there.  I think it may be a reasonable assumption though.

That cross section at the end of you post seems to sum things up quite nicely, I've been thinking on it, but I can't see any other alternatives for this location.  I think you've hit on the answer there!   

[JoeST]

This MD is beyond fantastic; miss Lora, you have blown my mind!!

The whole actually following maps directly I have tried before, I tried converted some maps of a book series I once read. I gave up quickly, due to inaccuracy in the drawing alignments between scale levels.

I sympathise with your technical difficulties. wifis are terribly inefficient, do you possibly have internet at libraries? I would suggest using either notepad or maybe something like DocRolarch's tools (on the STEX).

I will be following this place for as long as you update and will try and be as helpfull as possible with replies

Joe

[ldvger]

Ongoing Major Diversion #1: Novato Creek Dam

Joe, thanks for stopping by and I'm so happy you enjoy my work and the discussions going on here.  I look forward to hearing your comments again, and soon!  And yeah, translating fantasy maps to game maps is a whole 'nuther ball of wax.  If you could get a reasonable facsimile of the fantasy maps into Mapper or Terraformer, you could rescale it from there, I think, but not positive.  You might try looking over the forums hosted by the many mapping folks here and also over on ST to find out if anyone has developed a technique you could adapt.  Don't give up! 

And, not to beat what appears to now be a dead horse, but Battlecat had some remaining thoughts and ideas I wanted to address.  First of all, you had surmised a "high water mark" on the inside face of the dam, which I think may be an error in intepreted the aerial pics.  I have once again resorted to CAD to draw a quickie cross section through the dam that illustrates what I think we are seeing in the aerials:



What I think you may have done is mistaken either the line of the inside top of the old dam and the bottom of the newly added raised section as a high water mark OR mistaken the top of the newly raised top of the dam, which is flat and paved and a different color from the sloped inside face of the dam as a high water mark.  I have used Google Earth to look around the edges of the lake as you suggested, but in June of 2007, when this imagery was captured, the water level appears to actually be AT a high water point, as there are no beaches or mudflats of any extent anywhere around the lake and indeed there are some semi-drowned grasses among the reeds and aquatic plants that ring the lakeside.  There are no docks, just a single boat ramp on the far south west side of the lake for put in/pull out.  The dges of the lake look pretty nasty, actually, lots of algae and pond scu, floating around, especially at the western edges where it's shallowest. 

You also made some comments about shadows obscuring what is goin on in the spillway, so I made this little diagram to maybe clarify what *I* am seeing"



The most curious part of this image is that built structure extending off the left side wall of the spillway just below what we have come to agree is an outlet, the one I have labeled as "purpose unknown".  I am conjecturing, from what little I know about design of water control structures, that this is a force diverting or breaking device tp protect the left spillway wall from water pressure forces during times of flood.  IF the pipe carrying water from the lake to the head of the "natural stream" enters the headwater area at an angle, and IF the natural stream is allowed to overflow into the spillway during flood (and by flood, I just mean periods of high water or planned wter release), and IF both the spillway pipe and the stream pipe are metered to limit flow...THEN, it's possible that allowing both outflow pipes to run un-metered could create a lot of force directed at that left side spillway wall, especially if the spillway gates were also opened, partially or completely.  So my guess is this funny little flip of wall is designed to create an eddy at the confluence of the three possible areas of outflow and ensure that water from none of the three sources exerts too much pressure of the left wall but instead either flows down the spill way or backwashes back into the natural stream.  Just a guess. 

And lastly, you had conjectured as to where the natural stream joined the spillway stream, so I took a further zoom pic to show how I think they eventually join up and where:



A lot of the water flow is covered by trees, so this is really my best guess, but I know there is a stream entering from the north and under the main road that is also north of both the spillway and the "natural" stream.  Because the lake is primarily a source of drinking water and there is a lot of farming in the area, I figured the Water Department would want to keep the water coming out of the lake apart from other water sources as much as possible and close zooms, while blurry, do show that the spillway watercourse retains it's independence for other water in the area until it's past the treatment plant. 

In an interesting aside, while scanning the edges of the lake, I found a bunch of farmed/plowed fields above the lake (to the west) and they very nicely illustrate the RL application of the plowing technique I posted on your MD "Adara" this afternoon.  Don't worry!  I didn't take screen shots, so I won't be posting more images in your MD!  But, if you have Google Earth (and I imagine you do, you cartographer, you), you can go check them out for yourself and see what I meant. 

So, I think, maybe, we have solved the many mystreies of the Novato Creek Dam, with much help...thank you all very much!  I now feel confident of my ability to TRY to recreate it in my game, but I may get a little sidetracked getting the spillway right, as well as the water plant below the dam.  I've been playing this game since the original SimCity way back in 1992 (sheesh, that's a while ago, hard to believe so much time has gone by, 15 years!) and I have never tried my hand at creating custom content.  I think it may be time to open that Pandora's Box and see what happens.  As a designer of buildings in RL (when working, seems like another life, now after being out of work for a year), I think I'll start with the BAT, then go on to the Lot Editor.  I took a bunch of computer programming classes back in the mid 80's, which is a VERY long time ago, so creating MOD's intimidates me the most, which is why I will probably leave that for last. 

Remember the name of this MD is RECREATING San Francisco.  I'm not going to BAT every single building, but there are many structures that will need to be custom made.  My first try is going to be the water treament plant.  While a complex building, recreating it should be fairly simple, as it's a public building owned and paid for by taxpayers, so the plans for the complex are probably available via FOI at the Marin County Public Works website.  After 911, I know concern for protecting the nation's drinking water supply became a matter of heightened national security, so I may not have access to fine details, but I really don't need them.  A site plan and elevations is all I really need and I'm pretty sure I can get those online without too much trouble.  And I always have the aerials to fill in any gaps.  So...keep an eye out as Lora learns to BAT.

My next update will likely be the last in the series of steps to getting RL info into the game maps and if any of you folks are getting bored with all the many steps and details I address, this next update will definitely not be for you.  However, if you are fascinated by the working of minds focused on high levels of detail, then you'll be like a pig rolling in slops (being polite and PG, here).  I'm going to start the next update tonite, offline, because it will be long, and have both a lot of pics and text.  It may take me a day or two to put it together, as I must write a thank you letter to my uncle who sent me a check for $100 yesterday, thus reducing my dependence on my mom for my pocket money (if you can call buying denture cleaner, toilet paper, cat food, etc., "pocket" expenses).  I will definitely be checking back here and chatting between now and the next update, but just want you all to know the next one maye not be so quick to follow as has been true so far.

Stay tuned, please!  I enjoy all the feedback!

Lora/LD

[Battlecat]

Good point on that dam top, the added portion had slipped my mind.  Knowing that, I think you're CAD drawing is pretty much right on.  Certainly, there isn't any substitute for actually having a chance to look at what's up on the ground!  Your sketch of those natural water courses and the path of the spill way also makes perfect sense, particularly knowing that third stream is there!  I'm looking forward to seeing your first attempt at the BAT! 

Thanks for those shots of the plowing technique over in Adara!  I think I've got a couple ideas on what to do about that, but it's going to take some time to figure out how to accomplish it!  I certainly appreciate the illustration!

Keep up the great work, you've got an excellent plan in place here, I'm looking forward to see it start coming together in game.   

[ldvger]

Well, like I said, the next update will be long and full of pics and very detailed.  However, glad you liked tonite's update and we can but this issue of the mystery of the dam to it's final rest!

Lora/LD