# What are these large rectangular sand formations? **URL:** \ **Category:** Factual Questions\ **Created:** [March 2, 2009, 5:50am UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971 "2009-03-02T05:50:10Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![Bob55](https://avatars.discourse-cdn.com/v4/letter/b/e9c0ed/32.png) [@Bob55](https://boards.straightdope.com/u/Bob55)\ **Post date:** [March 2, 2009, 5:50am UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/1 "2009-03-02T05:50:10Z")
What are these sandy formations around Orlando, FL? I’ve been wondering for a while, and don’t have a good guess. Some of the Microsoft Live Bird’s Eye shots show grass in them, but why would they be in such strange formations, and in sand? Even if it is grass, or a crop, why such a strange setup? Below are links to both Microsoft Live and Google Earth of the location. [http://maps.live.com/default.aspx?v=2&FORM=LMLTCP&cp=28.491343~-81.61962&style=h&lvl=15&tilt=-90&dir=0&alt=-1000&scene=36341445&phx=0&phy=0&phscl=1&encType=1](http://maps.live.com/default.aspx?v=2&FORM=LMLTCP&cp=28.491343~-81.61962&style=h&lvl=15&tilt=-90&dir=0&alt=-1000&scene=36341445&phx=0&phy=0&phscl=1&encType=1) [http://maps.google.com/maps?f=q&source=s\_q&hl=en&geocode=&q=&gl=us&g=orlando,+fl&ie=UTF8&ll=28.493173,-81.627045&spn=0.022366,0.061798&t=h&z=15](http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=&gl=us&g=orlando,+fl&ie=UTF8&ll=28.493173,-81.627045&spn=0.022366,0.061798&t=h&z=15) ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [March 2, 2009, 6:05am UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/2 "2009-03-02T06:05:17Z")
They appear to be some kind of lined ponds, similar to sewage lagoons. It looks as if they are lined with a black synthetic liner. Perhaps they are sludge drying beds. Is there a wastewater treatment plant nearby? ---
**Author:** ![HomeBrewer](https://avatars.discourse-cdn.com/v4/letter/h/8797f3/32.png) [@HomeBrewer](https://boards.straightdope.com/u/HomeBrewer)\ **Post date:** [March 2, 2009, 8:31am UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/3 "2009-03-02T08:31:29Z")
sjr.state.fl.us/governingboard/pdfs/2005/rg0503/rg0503\_033.pdf This PDF seems to make mention of wet and dry retention ponds in that area as they relate to lane-widening road construction. I, however, am happily no longer working as an environmental consultant or permit engineer and so will leave the deep reading to someone else! ---
**Author:** ![Bob55](https://avatars.discourse-cdn.com/v4/letter/b/e9c0ed/32.png) [@Bob55](https://boards.straightdope.com/u/Bob55)\ **Post date:** [March 2, 2009, 1:16pm UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/4 "2009-03-02T13:16:53Z")
That is where they built the new expressway. It must have been swampland. I never would have guessed. Thanks! ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [March 2, 2009, 2:59pm UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/5 "2009-03-02T14:59:25Z")
If you’ll look at the photo and quadrangle map included in that linked report, this is not the same area. The widening of Highway 50 was over by Ocoee. Also, the ponds in the OP are too numerous to be the ones mentioned in the report. After reading through the report, however, I think they are recharge ponds for the underlying aquifer. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [March 2, 2009, 4:43pm UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/6 "2009-03-02T16:43:03Z")
They’re aggregate storage pits formerly owned by Rinker Materials. I have no idea who owns them now. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [March 2, 2009, 5:54pm UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/7 "2009-03-02T17:54:52Z")
> [@Really\_Not\_All\_That\_Bright](#): > > They’re aggregate storage pits formerly owned by Rinker Materials. I have no idea who owns them now. How does one load/unload the aggregate without disturbing the black liner? I see vehicle tracks in the material, hydraulic connections from one pond to the next, and two rectangular structures in each pond. These also have large levees around them. No offense, but I’m skeptical that these are aggregate storage pits. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [March 2, 2009, 6:27pm UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/8 "2009-03-02T18:27:46Z")
> [@NinetyWt](#): > > How does one load/unload the aggregate without disturbing the black liner? > > I see vehicle tracks in the material, hydraulic connections from one pond to the next, and two rectangular structures in each pond. These also have large levees around them. No offense, but I’m skeptical that these are aggregate storage pits. No idea, but I dealt with a case involving an injury at that location a while back. I don’t even know what an aggregate storage pit is, other than… a pit for storing aggregate. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [March 2, 2009, 7:06pm UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/9 "2009-03-02T19:06:22Z")
> [@Really\_Not\_All\_That\_Bright](#): > > No idea, but I dealt with a case involving an injury at that location a while back. I don’t even know what an aggregate storage pit is, other than… a pit for storing aggregate. Hmm. Supposing they were groundwater recharge beds, there _would_ have to be a separate place to store the aggregate which is used for the bottom. Perhaps your plaintiff was injured at the storage area, not these ponds? ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [March 2, 2009, 8:52pm UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/10 "2009-03-02T20:52:50Z")
Aha! Found them: > [@](#): > > Sand and water filters in Orange County, Florida treat wastewater for later reuse by citrus farmers. The farmers use the reclaimed wastewater to irrigate their orchards. Photo [here](http://www.waterencyclopedia.com/images/wsci_04_img0469.jpg). ---
**Author:** ![Bob55](https://avatars.discourse-cdn.com/v4/letter/b/e9c0ed/32.png) [@Bob55](https://boards.straightdope.com/u/Bob55)\ **Post date:** [March 2, 2009, 9:43pm UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/11 "2009-03-02T21:43:07Z")
> [@NinetyWt](#): > > Aha! Found them: > > Photo [here](http://www.waterencyclopedia.com/images/wsci_04_img0469.jpg). Good find. So they just pump water into them and let it drizzle through the sand to purify it? Maybe runoff from roads or something? ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [March 2, 2009, 10:45pm UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/12 "2009-03-02T22:45:27Z")
> [@Bob55](#): > > Good find. So they just pump water into them and let it drizzle through the sand to purify it? Maybe runoff from roads or something? Well, it says wastewater - IME that usually means water coming from the sewage treatment plant. However, they may mean something else, here - perhaps water which the orchard has used in its operation for irrigation, or washing of fruit, etc. The sand is meant to purify it, yes. Florida can use these sucessfully because their underlying soils are very sandy, and water will percolate down to the aquifer. Other areas, such as where I live, have very heavy, clayey soils and recharge beds do not work. ETA: these type basins can also be used to handle stormwater, such as roadway & parking lot runoff, as you mention. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [March 3, 2009, 12:55am UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/13 "2009-03-03T00:55:24Z")
Well, apparently I was _totally_ wrong. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [March 3, 2009, 4:15am UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/14 "2009-03-03T04:15:13Z")
> [@Really\_Not\_All\_That\_Bright](#): > > Well, apparently I was _totally_ wrong. Well - there has to be a place to keep all that sand. Sand can be termed “aggregate”. So somewhere at the maintenance place for these things, is a place where they keep the sand. So there _are_ aggregate storage areas associated with them. That’s just not what was in the photos. You were only _mostly_ wrong, not _totally_. 😉 ---
**Author:** ![AskNott](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asknott/32/5790_2.png) [@AskNott](https://boards.straightdope.com/u/AskNott)\ **Post date:** [March 3, 2009, 7:03pm UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/15 "2009-03-03T19:03:31Z")
> [@NinetyWt](#): > > Well - there has to be a place to keep all that sand. Sand can be termed “aggregate”. So somewhere at the maintenance place for these things, is a place where they keep the sand. So there _are_ aggregate storage areas associated with them. That’s just not what was in the photos. You were only _mostly_ wrong, not _totally_. 😉 After the sand has been used to filter a lot of ickwater, it’s probably trucked out to become concrete for sidewalks and highways. So it really is aggregate storage, and it doubles as wastewater filters. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [March 3, 2009, 11:19pm UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/16 "2009-03-03T23:19:23Z")
> [@AskNott](#): > > After the sand has been used to filter a lot of ickwater, it’s probably trucked out to become concrete for sidewalks and highways. So it really is aggregate storage, and it doubles as wastewater filters. That’s kind of like saying humans are vessels created to carry water uphill. If the primary intent of the structure is as a filter, then I wouldn’t call it an aggregate storage pit. I’m also dubious that contaminated sand would be used as aggregate. Do you have a cite for that? ---
**Author:** ![AskNott](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/asknott/32/5790_2.png) [@AskNott](https://boards.straightdope.com/u/AskNott)\ **Post date:** [March 4, 2009, 5:40am UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/17 "2009-03-04T05:40:21Z")
Hey, I was only half serious. However, it looks like green engineering to me. Instead of taking sand straight from a sand pit to the concrete mixer, use it first to filter wastewater. Then you reuse/recycle it as a roadbuilding aggregate. Where does it say roadbuilding aggregate has to be sterile? What better disposal than to encase it in concrete?😃 ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [March 4, 2009, 3:19pm UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/18 "2009-03-04T15:19:34Z")
> [@AskNott](#): > > Hey, I was only half serious. However, it looks like green engineering to me. Instead of taking sand straight from a sand pit to the concrete mixer, use it first to filter wastewater. Then you reuse/recycle it as a roadbuilding aggregate. Where does it say roadbuilding aggregate has to be sterile? What better disposal than to encase it in concrete?😃 Okay, I’ll lighten up. However. Aggregate for concrete has to be clean sand - in other words, washed sand. That’s for reasons of stick-to-cement-ishness. Dirty sand won’t perform correctly in the final product. Also, if the dirty sand had bad contaminants in it such as household cleaning chemicals, its use in concrete would not be permitted. I remember having a discussion here about reusing the sand from sandbags used in flood fighting - it’s a similar thing. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [March 4, 2009, 5:33pm UTC](https://boards.straightdope.com/t/what-are-these-large-rectangular-sand-formations/487971/19 "2009-03-04T17:33:42Z")
I realized something else. If roadway concrete is contaminated, then the stormwater runoff would also be contaminated. We probably don’t want that.