Ponds, Streams, Waterfalls & Fountains:
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Volume 1. Design & Construction
Volume 2. Maintenance, Stocking, Examples
eBook on Amazon
by Robert (Bob) Fenner
Small Pond Goldfish Pond Survival
I have a 765 gallon, irregular shaped, sunken pond. It is a 45 mil. EPDM
liner pond. It is a few weeks over 1 year old. It has a pH of about 8.
It has a uv, a fountain, and a submersible filter with a water pump of
about 625 gph. 2 of my adult fish died about 2 days ago. A calico
Shubunkin goldfish and a big white comet. They got gill damage. They got
it from being cooped up with 11 other goldfish. They were in a way too
small 50 gallon tank, with no filter or aeration. They stayed in there
for a day and overnight. My fault entirely. I should have known better.
I got 2 new replacement fish for them today. A little yellow comet and
another redheaded Shubunkin. They are both about 2 inches long. I live
in the Arizona desert. Will the 2 new fish have time to build up their
size and reserves before it gets too cold?
<Should do, but depends on how mild your autumns are and how cold it
actually gets in your winters. Remember, Goldfish can feed and
metabolise down to 10-12 degrees C, using low protein foods such as
wheat germ, but below that they shouldn't be fed anything at all until
springtime rolls round and it warms up above 10-12 C. Very small
Goldfish may do better overwintered indoors, and your 50 gallon tank
should be ample for that.
Mortality of yearling Goldfish can be quite high in cold climates where
ice forms over the pond, but Arizona might well be mild enough for yours
to do okay.>
<Welcome, Neale (in the UK). Have cc'ed RMF to add a more Southwestern
<<IF the pond is large enough, deep enough, protected by structure from
much influence of (weather) elements... to not vacillate much thermally
(see WWM re as always); the biota should be fine here. RMF>>
Re: Small Pond Goldfish Pond Survival
Thank you Neale! :)
Is the total # of gallons for my pond correct?
Current Water type
Type= Flexible EPDM .45 mil. liner, sunken
Site information= The site for my pond was a floodplain. It is mostly hot
and dry, floods during monsoon season. This flooding was taken into account
when pond was built. Cement wall was installed to prevent flood waters from
getting into the pond. The land is low-lying, with hard, gritty, sandy, soil
full of gravel.
14.1'long x 11.3 wide x 3.3' deep= total area dimensions
Underlayment= 25' L x 20' W
EPDM 45 mil. Flexible liner= 25' L x 20' W
Soft sand= 2" deep in bottom of deep area, deep end, middle, and shallow
No drain pipe necessary unless ground water is present during digging. No
drain pipe was necessary for this pond.
Cement wall around pond dimensions= 615" L x 6" W x 4" H x 4" Deep (51.3' L
x 4" W x 4" D)
Main pond dimensions (where the water is)= 12.5' L x 9' W x 3' deep
The pond dimensions divided into 3 different sections:
Dimensions for Shallow End
Filter box 1.5' L x 1.5' W x 11"D, total gallons= 2
Top part of shallow end 3.5' L x 4.10' W x 5" D, total gallons= 54
Total gallons for shallow end = 56
Dimensions for middle of pond
deep area 3' L × 3' W x 1.6' D, total gallons= 108
Top layer before deep area 5.8' Lx 6.4' W x 8" D, total gallons= 223
total gallons for middle of pond= 331
Deep End Dimensions
3.9' L x 8.11' W x 1.6' D, total gallons for end of pond= 380
Total pond gallons should be 767.
Is this total number of gallons correct?
<I do think you're close... There's about 7.5 gals/cubic foot, 231 cubic
inches per gallon... Another way of determining volume; should you find your
system empty at some point: Practice filling a known volume (e.g. a five
gallon plastic bucket) timed with a watch/device w/ a second hand/counter...
then with the hose turned up the same (all the way), measure how long it
takes to fill the pond... Divide by the number of second equivalents it took
to fill the bucket, multiply times five. Bob Fenner>
re: Is the total # of gallons for my pond correct? 7/9/14
Thank you Bob.
GF, pond size 1/1/14
Hello. My name is Joshua and I am 15 years old. First off, I would like
to thank the crew for all the help I've received over the years.
Between saltwater & freshwater, I've really learned a lot from your
website and it has been my "go to" website whenever I need a question
answered, or for a recommendation to others. But anyway, on to the
question! I've been a long time reader on WWM (about three years), and
I'm writing in today because I have a few questions regarding Goldfish.
I've noticed there seems to be quite a debate on the topic of Goldfish
pond sizes. Websites such as Aquascapeinc.com and
Watergarden.org (I will place links to the articles at the end of the
email) as well as several videos on YouTube state that as long as the
pond is over 10/20 gallons that any type of Goldfish can be added.
<No... foolish statement... First off, the "size" as in volume
is only one indication/limiter... the shape, and location... relative to
structure as well as ambient weather are important/critical as well.
Secondly, "it depends" on gear in use... There ARE some countervailing
heaters, filters, circulators, aerators... that can be used to crowd
goldfishes, but some/most varieties get too large for a system of only a
few tens of gallons>
They also say that Goldfish can limit their size to the
size of their environment.
<Not. I suggest these folks try living in a closet for a few
Now, however, your website states that stunting their size can cause a
variety of physical deformities, as well a shortened lifespan. My
question is, is there any truth to what they say? Can Goldfish really
live happily in such small quarters for long periods of time?
And would you consider the 20 gallon rule a good one?
Thanks for taking the time to answer this, it's just a question that's
bugged me for quite some time. ~Joshua.
http://watergarden.com/tub/index.html Ps. I've probably read all
the Goldfish pond articles and FAQs 10 or more times now. :)
<Cheers, Bob Fenner>
Thanks for the fast reply!
One last question: can Fantails be kept outdoors year-round?
<... if the system is stable enough, doesn't vacillate temp. wise too
much... yes. BobF>
How Many Gallons Would I Have... Pond project, reading
I am considering building a goldfish pond. I live in the Arizona desert.
<A nice project and fine place to have it... Do provide protection from
the sun... place near building/structure, build shading....>
I plan to make the pond 10 ft. in diameter by 3 ft. deep. Plan to use a
Butyl liner with a fine, soft sand as an underlayment. Underlayment will
be 1-2 inches deep. No plants planned. I am not very good with plants.
How many US liquid gallons will this pond setup hold?
<A few ways you can find out... mathematically... there's about 7.5
gallons per cubic foot... and the area of a circle is pi R squared...
times three feet of depth... R equals 5 (ft.), times itself is 25, times
pi... times three feet... times 7.5 (cu. ft./g)... about 1750 gallons...
More accurate likely to practice/measure filling a known volume, like a
5 gal. "pickle bucket... then filling the basin, timing how long this
takes... This is all gone over on WWM if you'd search>
I will be adding fish. Do not know how many because I do not know how
many gallons I have to work with yet.
Will be adding a pump with a filter too. Do not know which one to get yet
because I do not know how many gallons I have to work with yet.
<You've got a bit of reading to do... much better, and less headaches
and cost later. Start here:
and read down. You're welcome. Bob Fenner>
How Many Gallons 2... ? More re pond vol. measurement
Sorry. I neglected to mention I have a math disability. This makes doing
math difficult to impossible for me.
I found a simple calculation elsewhere that could also tell how many
gallons I have in my to be round pond. It goes like this:
length X width X depth X 5.9 gallons
<... what? In feet? No... see the prev. email... there are about 7.5
gal.s per cubic foot>
In this equation the length and width are the same.
If the pond is not round, the equation goes like this:
length X width X depth X 7.5 gallons
Using these equations, would I get the correct number of gallons for my
Butterfly Koi 6/27/13
I live in the Arizona desert. I have been thinking about ponds for
butterfly Koi. It will be 1,100 gallons for two of them. Let me know the
correct number of gallons for 2 if this is not right. How deep should I
dig my pond for 2 butterfly Koi? It is going to be a round pond. What
diameter should it be for 2 butterfly Koi?
<Please keep reading where I referred you to this AM. B>
Re: Indoor housing Koi 7/20/12
Thank you for the insight and the helpful information. We have found the
new house, and it actually has a water fountain at the side yard. It is
a courtyard that sees little disturbance and is well-sheltered from both
the elements and from most of the outstanding predators, though I don't
doubt a starving coyote or neighborhood wandering cat could jump the
fence. The fountain is not currently in use, and, if possible, I was
thinking of converting it into a small pond, with only a fraction of the
Koi, and house the remaining Koi with my friend, who is willing to take
on overflow. There are many issues, of course, with this, not knowing
the full history of the fountain, the fact that it is or was chlorinated
before the previous owners left, and the issue of materials.
The chlorine pump, if there is one, will be turned off or disconnected
entirely, the water swapped out and replaced after a good rubdown with
bleach, if necessary, but for the most part, a good scrub should do
It is full of algae, which may even have grown in the weeks since the
fountain was turned off. The water available has a good parameter set,
gH tested at about 160-180, and pH was solid between 7.0 and 7.5. So,
since the water is about the same as the water at my current home, I
expect the patterns of ebb and flow to be similar, with differences
attributable to external influence.
The fountain itself is 42" x 64" x 14".
From the absolute top of the fountain to the water surface, there is
about 6" of free space, but when taking the height measurement, I
excluded this space, so the actual water level was 14" from the
bottom.. I calculated the volume, and found that filled to
capacity, it would hold approximately 162 gallons.
Therefore, I intend to purchase an external canister filter capable of
operating for about 175 gallons, and will add some activated carbon
harboring bacterial colonies from my existing filters to the filter
media, if possible, will likely add a good amount of the water from my
cycled tanks, and will perhaps purchase several feeder goldfish to
create ammonia about a week after initial setup, then let the cycle run
for about 3 weeks, keeping a close eye on the water parameters.
<Just use a bit of food. No fish>
If the cycle is in adequate form by then, I will start adding my Koi.
However, the biggest obstacle I can see is the fountain itself.
The fountain is rectangular, and lined with ceramic tiles, and the
bottom of the fountain seems to be concrete. My concern here, of course,
is this material. The house, and the fountain, are not new. They have
been there several years, which may or may not have been enough
time for either anything harmful to have long-since leeched out of the
material, or for a sealing material to wear off and harmful chemicals
start to leech into the water. The fountain has raised edges with
ledges, and runoff does not breach the fountain. So, given all this, is
there a liquid Master Test Kit that tests for lye and other such harmful
chemicals that you could perhaps expect to leech from concrete?
<There is very likely VERY little of this at this time>
Alternatively, is there a product I can use to easily and effectively seal
the material to prevent the possibility of leeching?
Perhaps most importantly, can I effectively convert this fountain into a
small pond with one or two Koi, or is this an ultimately hopeless
If this is just impossible, then I will simply turn over the Koi to the
friend of mine with a well-established Koi pond, and instead opt for a
somewhat larger than "desktop" aquarium for my crayfish. Thank you.
<... best for you to keep planning on building a real pond in future.
December 21, 2011 1:15 PM
Subject: Indoor housing Koi
Before I begin, I would like to tell you that the arrangement is only
temporary, and I am very well aware that Koi cannot be expected to
permanently thrive in an indoor aquarium. However, for the time being,
the Koi are small and immature enough that the current conditions in
which they are being kept are sufficient. They receive a highly varied
diet of Koi pond sticks, freeze-dried foods, the occasional live food,
frozen food, and some fruits and veggies. They greet fruits and veggies
I attempt to introduce with tentative caution, but if left alone for a
while, eventually come to understand that they are food.
<Mmm, a good grade of pellets alone is fine>
They are currently housed in a 40 gallon tank with a filter that was
made for a 75 gallon tank, in an attempt to assure adequate filtration
during their stay. There are six Koi, most between 1-3" and one at least
However, they show no signs of stress or agitation, and even get along
with my dog when she presses her nose against the glass.
Now then, then only reason I opted to keep the fish indoors is because I
live in an area where there is a nature reserve pretty much in my
Coyotes and red-tails are a constant, and the coyotes have even learned
to imitate dogs barking to lure out pets. I have yet to see a raccoon in
the neighborhood, but I am sure they are here.
<Raccoons are tremendous Pondfish eaters; very hard to keep out>
The soil quality of the area is extremely dense, with about 2-3" of
topsoil, over a good 6" of clay. There are also very few pond building
specialists with the capacity to help me design a pond with the depth
and form necessary to keep these predators away.
<I will help you from afar if you'd like>
We may also move within a year. I perform frequent water changes on the
tank, usually massive, and done slowly and with minimal invasiveness to
minimize the stress to the fish.
<Do these weekly>
The water is cloudy, but it is a problem with the food I've been feeding
them rapidly dissolving into the water, and by doing the more massive
water changes, I am able to rapidly fix it. I plan to switch them over
to Hikari Growth Saki, if I can get my hands on it, or the readily
available steeple diets from Hikari.
<Both are excellent, as is the Spectrum pellet line>
The water I fill the tank from is hard with a solid pH of about 7.4 to
8, and the water is salted appropriately.
<No salt adding necessary or suggested>
I live is Southern California. Specifically, I live in Stevenson Ranch,
CA. Is there anyone, or any place that I can turn to nearby that will
help me to plan out an adequate pond or environment for my Koi?
<Here... as in WWM, and myself>
I myself am on a but of a budget, but am willing to devote any resource
necessary to maintain the health and safety of my fish. A neighbor of
mine has a pond, although it is not professionally constructed and
vulnerable to predators, where, if the need were absolute, they have
offered to temporarily house my Koi, should they outgrow the tank before
an adequate pond could be constructed, or should we move. Any help, and
an approximate estimate of how long it may take the fish to outgrow
their current home is welcome.
<Likely w/in a year... I would be very skimpy re feeding>
The fish are not mature, and I am not even able to determine their
genders, but they are healthy and active, and two have even become my
wonderful provocateur fish.
<Ah good. Do take your time, peruse the Pond Subweb here:
From the top down. Cheers, Bob Fenner>
Water Quality Problems with a Reflection Pool. Ftn. design,
I live in Ottawa, Ontario in a condo with a large reflection pool in the
courtyard. The pool measures about 25' by 50' and there is
room for the water level to be 7 inches.
<Ugghh! Hard to keep such shallow systems chemically
Right now, however, there is a layer of small pebbles on the
bottom so there is only about 4 - 5 inches of water.
<Yikes! Even worse!>
The pebbles have trapped dirt over the years and they hold a bevy of
sludge and other impurities. The pool originally had new
water added continuously with the old water going down the drain.
When the city started to charge for water, the pool water was recirculated
to avoid waste. The pool is in the sun for most of the
<Good gosh... do you have numerous ducks as well?>
We have a fountain in the middle of the pool that gives a nice effect
but does little to circulate the water. We have added a second
pump to push water around the perimeter and we place chlorine
pucks in front of it.
<... one approach. You need to have... measure, maintain "conditioner"
(see the pool folks, biz); and monitor pH and alkalinity as well>
This has had little effect other than right in front of the outlet.
Needless to say, with the hot weather comes algae. It is only June
and we have had to empty the pool and start again.
The water does not circulate and the chlorine is not sufficient to stop
any algae build up.
We are contemplating some changes to improve the water circulation but
are uncertain of the effectiveness of each. Both options
include eliminating the pebbles in the pool.
<Yes I would... or at least mortar them with just half or less of their
faces exposed... for ease of vacuuming, cleaning>
The first option would be to replace the liner with one that would allow
a water depth of 9 inches as we are told that this would allow for the
introduction of plants that would help to purify the water.
<Mmm, not worthwhile; no. This is still way too shallow>
This is somewhat problematic as we are told the plants would have to be
stored somewhere over the winter. The second option would be to
increase the circulation with either a 6-7 inch depth or a 9 inch depth
if necessary and introduce a chlorination system of some sort to keep
the water clear. Under each option, key to success, we believe, is
to increase significantly the circulation of water in the pool.
<These would help...
We were wondering if you could provide any advice on the relative
effectiveness of plants vs. chlorine in keeping the pool water clear and
on an appropriate circulation system (capacity and type) to keep the
water moving and clear. Would either scenario require raising the
depth from 6-7 inches to 9 inches?
<Won't help much... I wouldn't advise it. IF the area around the feature
could be built up... above grade... to eighteen or more inches... this
basin could be made biological>
How effective would reducing the size of the pool to about 25' by 30' be
in providing an effective solution.
<A percentage by volume...>
We would greatly appreciate any advice you might be able to give.
<Mmm, there are a few moda chemically to consider other than the current
chlorine/pool/spa... Some are toxic to surrounding landscape... so if
there's much splash, spray from the central jet... I might well propose
abandoning this water feature altogether (it can't be made either
serviceable or functional really... and replacing it with more garden...
art... benches, a contemplation area. Bob Fenner>
Will my 'pond' support my goldfish?
I have 2 beautiful goldfish, a common (male) and a Sarasa comet
My comet is around the 14cm mark (inc. tail) and my common is around
11cm (inc. tail). They are residing in a 40 gallon pond.
<Mmm, too small a volume to be "very" or sufficiently
stable... even in a tropical latitude>
I have an old (yet working fine) sponge filter and pump in with them,
in addition to 3 goldfish-mangled plants (2 Vallisnerias and 1
I do weekly water changes of 60%.
After reading many, many different websites each with different
opinions on the amount of litres suitable for an adult single-tailed
goldfish really is, I am very confused and unsure.
February this year, (3 days after moving into the 40 gallon) from a 10
gallon) they spawned for the first and only time. I was wondering if
they spawned again if it would be an indication of happiness in their
I am unsure as to whether or not this is relevant as I have been able
to find hardly any information on this subject, my Sarasa comet is a
linear-scaled goldfish ( very beautiful!). Will she grow any larger
<Yes... all goldfish are the same cross... akin to domestic dogs,
cats... Can, will grow to more than a foot in length given propitious
So, in conclusion, I was wondering if 40 gallons will suffice for these
two fish, and if not how long do I have (if not already) before they
will be impacted upon and if there is anything additional I can do to
<Are already being slowed in their growth here... Need at least a
hundred gallons or so to "realize their potential">
Thank you sincerely, Amy.
<Welcome. Bob Fenner>
Pond construction, shape... liner use 6/6/09
I'm building a raised formal geometric shaped Koi pond.
<Mmm, beware of "tight corners"... for your fishes
(Nishikigoi "panic" at times when "caught in corners),
as well as circulation and all it entails reasons>
Concrete block walls with sand/cement hard bottom and liner.
#1....in regards to the liner, is it possible to cut it into sections,
align them (with overlap) and "weld" or bond them together to
make a form-fitted liner in order to avoid unsightly wrinkles and
<Yes it is possible. Do be sure to check re the type of
material/solvent for welding (we used tetra hydro furane for PVC for
I'm a fairly "handy" guy and I'm not afraid to try
anything at least once!
#2.... I plan to install a VERY heavy cast concrete statue (fountain)
in the middle of the pond, with its base just below water level,
resting on an "island" of concrete blocks (4 ft pond depth).
My thoughts are these;
poured concrete footer, an underlayment, liner,
<Mmm, the underlayment first... perhaps a piece of carpet... then
then concrete block "island" mortared above, and of course
the statue on top. Obviously an enormous amount of weight. Any advice
here? Thank you in advance.
<Enjoy the process. Bob Fenner>
Pond... plumbing, shape design... 10/3/07 Hi folks, I
respect your request for avoiding questions that the user could find in
the FAQ or with Google. I found your site with a Google search and I
don't see my question answered anywhere yet so hopefully, I am not
creating undue burdens here, and thanks very much for setting up the
space to ask. <Welcome> I am now facing taking over someone else's
project at mid point. The contractor apparently had a shady side and is
now in jail. <Yikes!> Looks like promises were made and not kept
about what was ordered, etc. I was looking at the hole he left last
night and I am researching all I remember from my own pond building and
pond maintenance days and my landscape design classes to see what I
would need to pull this off. I used to work for a relatively high end
pond and water building firm in the DC area. I dug holes, moved rocks,
ran equipment and most especially did lots of maintenance on filters
and ponds. I never felt responsible for designing the whole thing,
engineering the plumbing although I have certainly fixed broken pipes,
valves and pumps. And I have some awareness of waterfalls, stream beds,
construction and (gulp) leaks. I have also installed some small
features for friend's and I usually build my own filters to sit in
the pond. This project will be one, or two steps beyond what I have
already done. And, I haven't been in the business for over ten
years so I am internet researching to job my memory of what we used to
do. <Okay> The size of the pond is roughly 15 x 30 feet. On the
deep end it looks to be over 6 or 7 feet. <Good-sized... what do the
folks in charge "want it to do?"> The pond is roughly
kidney shaped and it is already dug out. The contractor left a layer of
plastic sheeting over it like a liner, I don't know why. The
homeowner said the contractor said he did it to dry out the ground (?)
<?> Is this a technique that sounds familiar to anyone?
<No> First step would be to remove it as I am going with my
experience installing the underlayment and the EPDM liner. <Good>
The first thing I notice is there is no work started yet on the
plumbing, no skimmer, no trenches or pipes, no bottom drain. So my
first question is, common sense from a maintenance background is to
install the bottom drain. There is no hole or trench dug for a bottom
drain so I have to take care of that too. But I need to research how
that works. I have seen it working but I can't remember
"how" it runs. I am a little confused with all the different
installations I was a part of and I hope I am not mixing one idea with
another? I have seen skimmer boxes with the pump inside them. <Mmm,
really?> In that case water is sucked into the skimmer and pushed
through the pipe up to the bio filter which doubles as a waterfall top
edge. <Have seen these...> In other systems the filter or filters
are vortex, bead or other external variety, usually with high nitrate
producing Koi, are outside the system and isolated a bit to take the
pump sounds away from the pond design. I think this would be over kill
on this design for what the customer wants. <Good units... pricey to
acquire and operate, but work> I also know there is value in adding
a waterfall pump and having a regular circulation pump. This allows
energy savings when you want to keep your system filtered and healthy
but not pay the electric bill or possibly generate noise all the time
with the full force of the waterfall. It also allows for maintenance
and adjustment to the waterfall without hurting the pond system.
<Well-stated> That's what I know. What I don't know is
about how to set up a bottom drain and valve it to the flow of the
skimmer? <Mmm, can be done through the membrane (with flanges) or
inside... via trenching in both... the main drain plumbed to the
skimmer directly if one wants... with the second/behind hole going
up/out of the system to the pump intake... but I encourage you to have
at least two intakes... if you want a skimmer (or two), plumb these AND
the main drain separately out, up to the pump...> If I take on this
design, I am thinking that the pump needs to pull water from both the
bottom drain line and also the skimmer. <Yes, this is best> If
true than the design with a push pump in the skimmer would not work.
<Correct... and I am NOT a fan of submersible pumps...> Is this
true? Therefore if I used a bottom drain I would look at designs with
the pump in the biofalls or free standing outside or behind the
waterfalls. I would need one of these designs to achieve puling the
water up the button drain and the skimmer, yes? <Yes> And if I am
on the right track there, then I will need a valve to adjust the rate
of intake between the skimmer and the bottom drain, Yes?
<Correct> If I read correctly, there is a reason to completely
shut off the skimmer if necessary to feed the fish or for skimmer
maintenance and if I designed it correctly I could just valve to the
bottom drain 100% with no worries. Yes? <Yes> Can someone please
refresh my memory as to what is the usual percentage of flow between
bottom drain and slimmer to the system? <Mmm, less to the
skimmer/s... ten-twenty percent or so; the remaining from the main>
Assuming that in large part this is something you observe once it is
running but there should also be a rule of thumb here. <Yes> If I
read on line articles right and compare that to the ponds I have
installed in the past, I believe you don't want the water fall or
pond return flow too near the bottom drain, for achieving good
circulation mainly. But that is how the contractor has set it up so is
this something I should really consider doing differently or is it
really going to be a problem? <Not likely a problem> I should
mention that although I see the wisdom of a bottom drain, if it turns
out to be out of the homeowners budget or not completely necessary, I
want to consider the design without this feature. I assume this takes
me to the simplest solution mentioned earlier of putting a pump in a
skimmer box and running a single line to a biofalls. Yes? <... not
if it were my design, no. Much to be related here... the best
engineering involves a "passive" system of plumbing that
conducts water NOT from the bottom, but maybe 3 or 4/5s the way down...
this water recirculated... and a bottom "drain" in addition
to simply dump the "bad water" from the bottom itself...>
The other question I have, also important, is about pond construction.
This is Denver. I am writing this in early October so I may have a
month left before the ground gets too solid. Or, I could have two
months let, you never know around here. I am sure there must me what we
called frost heave back in Virginia, here in Denver. YOU have to build
with a mind to the changes in the soil when it freezes and thaws again.
<Yes> With that in mind I want to ask about the technique that I
remember using and ask for some feedback to see if what I am thinking
of doing, makes sense to an expert? <Sloping sides, good landscape
drainage, perhaps a sand bed arrangement around the basin, not leaving
the system empty during freezing weather> I am used to digging more
or less vertical walls in the dirt and taking the top 18" down for
setting one or two cinder blocks, depending on the strength of the
surrounding soil. We laid the cinder blocks on the side and filled the
holes with tightly packed dirt. Then we rammed pieces of rebar into
each hole. We built some very nice high end designs this way and while
it stabilized the bank, or seemed to in the Virginia clay, it also was
a way to provide a stable base for large heavy rocks that could be put
next to or on, an edge. <Sounds very good> I see lots of
"how to's" on the web about building cinder block walls
form the bottom of the pond, but none using the techniques I am
remembering. <I am unfamiliar with this as well> The contractor
left long sloping edges that I don't like very much. They slope
nearly 45 degrees around the shallow end. <Mmm, yes... not good for
maintenance, but better to avoid having the basin crushed, pop-out
during coldest weather> It seems more natural to my mind to cut the
edges more to a vertical angle, possibly leaving ledges (yes knowing
about predators and ledges). Is there any reason a design would have
such largely sloping edges that I am not aware of? It also seems more
potentially stable to make a proper wall at the start. And that means
pretty much vertical with soft rounding on the bottom edges, more art
than science but then, I have been there and done that before. <As
stated> Thanks much folks. I know I am asking a lot but I hope my
questions have provided enough clarity for answers. I would recap this
into wall constructions with cinder blocks on the top layer only and
bottom drains and system choices for pond mechanics. If you post my
question and your response please omit my phone number and email.
Thanks. David Groover <Am unfortunately going to be out of Net reach
for a couple of weeks soon... Bob Fenner>
Pond Overwintering, not reading
8/19/06 Ok well I live in Pennsylvania where it is
pretty cold and the pond will freeze. How deep does it have
to be. <Mmm... depends on what you intend to keep in it, where
it's located relative to "structure", whether you intend
to employ countervailing strategies to prevent it freezing over/all the
way to the bottom... 4 to 6 feet likely...> Also is there any
specific brand of food I should feed them or what should I
feed them to get their fat up for the winter. <Please read here:
the linked files above... Bob Fenner>
Pondfishes in the GWN 3/3/06 Hello I am thinking of
setting up a small outdoor pond - 180 gallons - which contains no
heater and a basic filter. <... likely too unstable at this
volume...> I am located in Nanaimo, British Columbia, Canada. I have
a couple of questions: What type of fish would you suggest? Can they
survive the winter? <Perhaps some of the local life...> What
happens if the water freezes in the pond? <If all the way down,
fishicles... See WWM re ponds please: http://wetwebmedia.com/PondSubWebIndex/Pond%20Sub%20Web.htm
See all those blue file names? They're links... Bob Fenner>
Thank you Pat
Pond article Corr. 1/20/06 Your article was most
informative. However, please change the spelling of the word
"irregardless," found in the first sentence of the
section entitled, "Shape and Size." There is no
such word, it should be regardless. <Thank you for this. BobF>
<<And looking on Google... there's a few pages of
others...>> Pond depth, poor English 10/13/05 I am digging
a small backyard pool (wildlife area) about 15 feet long &4 to5
feet wide .I want to put a few medium sized fish in it .I started
digging it two feet deep .is this deep enough or would 18" be
enough? Don <There are economic, practical and legal inputs here...
Please read: http://wetwebmedia.com/PondSubWebIndex/pddessize.htm
and the linked files above re. Bob Fenner>
Tropical Ponds Bob, I see that you answer all the questions
regarding ponds on the WWM.com website, I apologies for the length of
this email, but figured better to send all the details. <Good> I
have read through the pond section at WWM.com and found it to be very
informative, however I have been unable to find anything on tropical
ponds. I live in Thailand and the availability of pumps, accessories
etc for pond construction is very limited and for that reason most of
the construction will be DIY. I have a number of questions that I have
been unable to find the answers to that I hope you can help me with.
Background details, (The Plan!). Construction; liner with reinforced
concrete and then Thoroseal, (or equivalent if I can find it). Pond
shape; roughly pear, 5mt long x 3mt > 1.5mt, 1mt high waterfall at
the 3mt width end. Plumbing ; 4 x 2" outlets, (with debris traps),
set in the bottom of the pond going into a pre-filter using round
stones or rough plastic balls. The inlet to the pre-filter would be at
the same level as the 4 outlets. From this the pump suction would be
approximately 3" below the water level of the pond. Pump discharge
is 10.5 Lt per minute, which will go into a filter. The filter will be
3 stage type using; settling, plastic hair curler type tubes and then
into to the bio-filter chamber and then into the top pool of the
waterfall. I will also include drains/by-passes and back-wash piping
for cleaning in the final design. <Does sound like you've been
investigating. Sounds good thus far> The Questions * Most articles
recommend a water depth of 3ft, I found 1 forum article regarding warm
water ponds which said this type should only be 18" deep. What
would be the recommendation for a pond here in Thailand, average
temperature 28'C, 83'F? <I would make the pond deeper...
more stable all the way around, should you find that you want to keep
fishes that appreciate smaller shifts in temperature, dissolved oxygen,
pH... Easier to maintain if deeper as well> * The pond will not be
shaded, should I use a UV filter? <If suspended algal over-growth is
an issue, yes> * Can you recommend any books, web sites etc on the
subject of tropical ponds, with sections on the type of plants and fish
species that can be mixed etc. <There are many... some in English by
Tropical Fish Hobbyist Publications, some in Japanese. None are
definitive IMO... I encourage you to try getting, reading what you can
from a larger library, but as importantly to seek out others (maybe a
pond society there) who have built similar systems in your locale, the
input of concrete contractors, landscapers... and the input you can
garner from the Internet (on various bulletin boards, chatforums) re
ponds. You have a good grasp of what this project is about and will do
fine investigating, keeping good notes, sorting out your options.>
Many thanks in advance for any advice you can offer. Regards Neil
Sandilands <Bob Fenner>
Re: Tropical Ponds Bob, Many Thanks for your prompt reply, I
apologize that mine was somewhat slower, but my work location sometimes
has problems with internet connections. <I understand...
completely> I will definitely go deeper as recommended and try and
find some books/contacts in my area, I'll see what happens
regarding UV. I anticipate around 6 months for construction, (due to
work schedule), hopefully all will run smoothly. Thanks again. Regards
Neil <Ah, a grand adventure. I was/am involved in a couple of
"authentic" Japanese ponds that started construction before
my joining and are still "being built" more than three
decades later... these "things" take time... Enjoy the
process my friend. Bob Fenner>