Swales: Earthworks for Conservation and Storage [PDC Preview]

[@soniaquijada-ramberger]

I have started a small swales on my property. Neighbors slow down to see what I am doing…even a plumber, who I called to repair a busted pipe, was intrigued and asked where the trench was headed to? Serendipitously I began the swales in my backyard. I continued digging the swales up to an approximately 30 ft. Sugar berry tree. A lot of physical work…it’s worth it for various reasons.

[@sharifhussein5747]

The best teacher ever, we're grateful for the knowledge you're selflessly sharing.

[@Eric998765]

I've been following Geoff for ten years and still learned new stuff from this video, such as swale spacing by tree height

[@deanpd3402]

He is always good to revisit, especially after we have done work implementing PC systems.

[@capeeddy]

I've seen a dozen or so of your videos in the past two days and I'm learning A LOT of new things from you. Thank you very much!

[@TheWeedyGarden]

You are not alone Eddy. I am too 💚👍🏼😊

[@capeeddy]

@@TheWeedyGarden I've seen all of your videos and they're impressive, creative, and informative. Thank you sir!

[@ahmadhasif979]

Me too, i even make new playlist

[@ahmadhasif979]

@@TheWeedyGarden it's all because your video about visiting zaytuna farm 😂👍🏽👍🏿👍🏼👍🏻👍🏾

[@TheWeedyGarden]

@@capeeddy thanks Eddy 🙏👍🏼🖐🏼

[@k0mm4nd3r_k3n]

18 mins of Geoff talking about swales is the content I need in my life

[@marialaskari2903]

I love your videos so much! When I discovered your existence and permaculture 8 years ago, I was an apartment dweller. Now 8 years in, I am on my own land making my dream food forest reality every day! I am so thankful for you...and the playfully joyous way you share your knowledge....It truly makes a difference! Rock on!

[@alisonfayers-kerr9089]

This is the best explanation of sales EVER. I have seen many. People who criticise swales, don’t understand the principles; either that, or they aren’t incorporating them into an overall project based on Pernacultural Design.

[@ryanlove8242]

Thank you so much Mr. Lawton! I am so grateful for your teachings and content. My quality of life is getting better every day because of what you taught me. It is an honor and a privilege to have you as my teacher. A lot of hungry people in need are going to get fed because of what you taught me. God bless you! Much love and thanks from Aromas California!

[@Нарангэрэлэнэхэнбэ]

Good luck, Ryan hope you all are doing well/

[@davidgordon5205]

You Geoff are as beneficial for mankind as much as the swales are. Top job mate.

[@kikikut22]

The planning for initally "lower quality" trees to "higher quality" trees once the predictive soil fertility improvement occurs is instructive of the usual understanding of planting "native" over "invasive"

[@abundancejourney8316]

I deeply appreciate the education you are providing..it boggles my mind this extremely valuable knowledge isn't taught in any school curriculum. Teachers like you are opening my mind and heart to a different way of life, and just like a plant...EVEN IN THE DESERT, ill grow.

[@medahenderson3055]

Wow!! I live in southern AZ, and always thought this would never be possible- but you are so right... The San Pedro River is right close to where we are in the desert and it incorporates this exact technique - swales with trees on slopes and natural composting from organic falloff of trees and run off from the slope of the mountains on both sides!!! I need to incorporate this tech in MY acreage!!! planning now- thank you so much for sharing your insight and knowledge for free! Lord Bless you!

[@iwanabana]

Update us please!

[@AlpacaRenee]

I’m in southern Az too. Isn’t this exciting?!?!

[@carmenortiz5294]

Years ago I took a free online course by Geoff. It consisted of many separate videos. I spend an entire three days non-stop watching one after the other, they were that interesting! (I did take bathroom and eating breaks, lucky I'm one of those strange people that only need 3 hours of sleep, but that time I did not take any sleeping breaks.) Been a fan since then.

[@chadstreblow3543]

I recently purchase five acres of slightly sloping desert land and have been considering how to bring the land back to life. This information/concept is so simple yet so earth shattering at the same time. I can’t wait to get to work implementing this on my land. Thank you so much for sharing your wealth of knowledge.

[@calebhudson4313]

Geoff Lawton, you helped me believe it's possible to build a 5 acre food forest. Thank you for the leg up.

[@lesliekendall2206]

You're a swale guy. 😊

[@jameswaterhouse-brown6646]

Ha!

[@chandanakarunarathne1624]

I see you as a genius. A very practical man among many conventionally educated crowd. Really appreciate your content.

[@craigslitzer4857]

2:19 Thank you for addressing this tiny detail! It's a question I've had for several years and I now finally have an answer. I've never been sure whether swales in my area would be a benefit or a detriment, and this resolves the dilemma.

[@adingo8mybaby]

Thinking about putting swales across my 160 acre property this gave me a lot of food for thought! Thanks Geoff.

[@nessav7258]

just need the machine now

[@adingo8mybaby]

@@nessav7258 I got a 1970 hanomag 10 ton drott 🤠

[@mikedoyle9934]

After learning about the hedgerows in England and the isles it's reminded me of a ditch style where the dirt from the ditch gets put in between two laid rows which built a live wall of sorts. Hedgerow paddock systems with swales and ponds as a foundation is a potentially potent mix.

[@PsychicIsaacs]

I live in semi arid North Central Victoria, Australia. I plant Nopal Cactus (Opuntia ficus indica) on the mounds of my swales. They are a pioneer species that roots and grows quickly, binds the soil and increases fertility. They are an excellent nurse species, providing shade and wind protection for more delicate plants, they also grow one of the most delicious and nutritious fruits you will ever eat and you can also eat the pads or feed them to livestock.

[@ahmadhasif979]

For me It's all started from YAKUBA SAWADOGO, the man who stop the dessert. We save our planet stop soil degradation

[@danthadon87]

Great teacher makes it easy to understand for the layman.

[@daleo2536]

Another brilliantly presented episode. Thank you Geoff for such an informative and simply described explanation of how swales work.

[@mackenziemoyer9180]

I'm an instructional designer and eLearning developer. I'd love to work with Geoff on this gold content.

[@megaarbok3290]

You can hear the wildlife the entire time, this is permaculture!

[@EliTeAkheton]

Geoff please post a tour of your property and how you've managed these devastating rains

[@TheWeedyGarden]

Another very good explaination Geoff. Thank you so much for sharing. Great video. 🙏

[@user-qf3lq4zj8g]

Good to see you here Weedyman. I am already imagining your weedyfood-forest growing weedyfuly magnificent.

[@TheWeedyGarden]

@@user-qf3lq4zj8g Oh yes. So can I. Already started planting. My first tree was a little healthy Bowen mango which I planted on the last video. Totally getting into his PDC course ATM. What about you?

[@user-qf3lq4zj8g]

@@TheWeedyGarden yes, that mango tree must feel like singing "I'm on top of the world"! I haven't missed a single video you uploaded Mr. Weedyman, I even got to watch the first hilarious version of your Compashi video! 🤣 You inspired me to get closer to Earth and I knew about Geoff before, but it was your recent videos that got me digging into patterns and design more seriously. I am grateful for that and I hope to dig even deeper as soon as I got a few of my responsibilities sorted out. Keep up the good work, plant plentifully and time-lapse whenever you are able to! People love watching living things literally grow in front of their eyes 😉

[@TheWeedyGarden]

@@user-qf3lq4zj8g I love doing time lapse but only have one camera 😓

[@PaleGhost69]

Does anyone else have a problem with their brain driving them crazy by designing every piece of lawn they see into swales and food forests?

[@jameskniskern2261]

I call it permaculture brain. The program is always running. It is especially challenging as I drive on highways and see large sections of properties and realize what could be.

[@PaleGhost69]

​@@jameskniskern2261 Glad I'm not the only one.

[@gwynnethvanjaarsveld7030]

Yes,😂

[@lawntofoodforest]

It’s the labor that holds me back, breaking my back just swaling my own patch.

[@PaleGhost69]

@@lawntofoodforest See if you can organize a permaculture work party with locals that might be interested. Personally, I'd love to come help but everyone around me is high on the smell of gas and cow farts.

[@josephinequarcoopome9348]

Excellent tutorial especially for those who have need of the principles contained in this tutorial, one of which is an interdependent Ecosystem in harmony with Man, water, trees, manure & mulch, and even ducks. Thank you.

[@insAneTunA]

Hi Geoff, I just want to say that you are doing an awesome job. I am wondering how you are doing since I have been hearing about the floods in New South Wales. I also wonder what your opinion is about the flood situation from a permaculture perspective. I mean, do you think that these floods would be preventable or manageable if the surrounding land was treated according to the principles of permaculture? Strange enough it all seems so related, first the fires because of the severe droughts, and now the floods, all because of the poor soil conditions. Right now nature in Australia is in a downward spiral and the situation is getting worse very rapidly if nothing is done about it. I truly hope that one day Australia will get a prime minister who will understand nature and what a healthy ecosystem does and means for the land and the people, and that the solution is Permaculture. Australia, and I mean the entire country, could be a lush forest, with plenty of food for the whole world.

[@melissaojala855]

That is a really good video. I was confused about what type of swale to build but now you've answered my questions. Thank you!

[@antoniodossantos5960]

Thanks...Geoff🌎

[@wudangmtn]

Great info, thank you sir. I hadn’t thought about the spacing, that is good to know. I also did not know that gypsum and grooves could be added to a swale. I have clay soil.👍

[@glenpryce]

Great stuff Geoff. I am currently installing swales and thought they were a very simple beneficial feature but you have provided a few simple but very beneficial extra elements that I can apply. Thank you😊

[@jettyeddie_m9130]

Thanks geoff 🙏

[@tuffy2242]

yep - GEoff is the best teacher ever👌💪

[@tuffy2242]

the whole permaculture course is amazing..highly recommended

[@crpth1]

Regarding the video content evaluation, let me put it in simple terms! AWESOME! This type of content makes me want to get the time and money to make a full permaculture course with Geoff! ;-)

[@dreamreal756]

Amazing to have such good information available.

[@iTeerRex]

Mr Lawton, you said swales are not for steep slopes. Why is that and what angle is considered steep? Thank you.

[@downundervlogs]

This is certainly a perfect way to ensure water catchment and improve growth and environmental protection. Creating oasis in some of the most desolate places and enhancing green growth and life for organisms and microbes to flow through and create such lush grounds. Very well explained.

[@gcb6185]

Thank you Mr Geoff great mind even you surpassed your teacher Bill we can keep on listening these stuff wow what an understanding you have , great teacher, thank you

[@nikkimachowski5553]

I am learning so much from your videos. I am looking forward to learning from you when you are in South Africa.

[@cdgggg]

This man is hero :)

[@JaimeBird-n8m]

Helpful information we are just putting in swales taking your information with our hard work to build soil from clay loam to wetter with high organic matter

[@honzacapek2571]

Too bad I was too young when I was living in Sydney... I would have visited Zantuya farm a maybe stayed there... Now I am back in Czech Republic and getting tired of long winters where every gardener needs to wait for spring such a long period of cold winter...

[@louisegogel7973]

There are ways to extend the growing season in cold climates too… a good compost heap can produce a ton of heat for a small greenhouse. And if you include animals in the greenhouse, then you multiply the heat production as well as fertilize the soil. Keep an open mind and look for ways that nature already has figured this out. I bet Geoff addresses in another video and in books exactly the issue you have presented here.

[@JeremyHoodDaniel]

I have terraces on my hill, built centuries ago. And I cut cross drains so as to keep soil run off on the hill

[@barbarajuneelder20]

Brilliant! Thank you sooooo much! from Costa Rica.

[@BishoTren]

I’d love to hear your thoughts and ideas for permaculture on my west Australian property which has roughly 400mm of rain annually.

[@nessav7258]

I think one of the Q & A videos answers this

[@jarrohyndman9430]

Wonderful program very informative thanks

[@healthdanab4421]

I'm in late spring, on an acre of flat, dry, weedy, and in some places very compacted, dirt. But Im gonna make swales as a wind buffer from the west/northwest, propogate a bunch of tree legumes from a nearby young forest, grow some cover crops, and fertilize everything with biochar/and compost. I'm gonna build my swales like hugelkulture beds but use biochar instead of logs. I'm putting evergreens vines and fruit trees on the the west and nw eprimiter of the whole place too, and especially around my house to keep it cooler since i don't have a good ac, and I'm in the csa hot summer Mediterranean climate of ca. I wanna get a 55 gal barrel and make compost tea too.

[@willbrooks9466]

Brilliant! Thank you and keep dropping these knowledge bombs! I am looking forward to the class, I will be signing up.

[@mainerockflour3462]

Your initial cross-section of a swale early on resembled my girlfriend's outline. Then when you placed trees on her "behind", you killed me! They looked like 'puffs'! 🤣🤣🤣 Thanks mate, I need the laugh.

[@subeed76]

Geoff, amazing videos as always! However it is very hard to find videos on swales for small gardens like 1000sq ft area. Can you pl share your valuable experience on designing swales for small gardens

[@louisegogel7973]

I have seen people use rocks to build water catchments along the contours of the landscape, and even those tiny single to double layers of rocks slow the water and let it sink a little bit. Mulch covers the rocks eventually, then more rocks can be layered on the previous, now covered rock layer.

[@christinebottaro9017]

I wonder about standing water and mosquitos. Any comment on that? Also, is Keyline Design essentially the same thing?

[@louisegogel7973]

I suspect a lot of these areas don’t hold standing water for long enough to have an issue with mosquitos, and if they do stay wet, then I imagine various predator species move in to take advantage of the food supply.

[@bismanaufa5618]

We can put small fishes to eat those mosquitoes larvas

[@Nature_Inna_Box]

left this video loving swales lol. awesome teacher

[@drakthorzodin-son3643]

So if this land deal goes through i will be committing to trying to green up desert land in arizona. I was going to incorporate the idealogy of swales but in more of an orchard environment. (i like the idea of maybe drip line irrigation and over watering at sun down and 2 hours before sun up if i can) but build in swales to act as duck ponds. I think im going to intercrop moringa or honey locust with fruit trees and possibly dig the swales slightly with just a shovel as a test project in an 100x100 closed off area so i can incorporate ducks/geese while having enough for them to hopefully enjoy some water baths. and during growing season run watermelon/squash etc planted by the swale/dug out alley way line and letting them grow rampant as they want in the tree line acting like a really good cover crop that turns into animal feed or mulch post harvest. then run set of meat duckies right on through post harvest. The other idea would be to get tractor somehow and dig 4 feet down (2 foot card board 1.5 foot compost .5 foot mulch while mounding the sides a good bit. drip hose/tape irrigation down the swale area and in the alley cropping area possibly extra moringa trees in the middle to be coppiced (maybe 20% mulch and 80% animal feed/fodder) I am ok with importing as much water as i need to get this set up working as long as i can get enough profitability off of the project. Also will be starting with 6 total 100x100 areas. with the center area on the north side (north hemisphere so want to shade out the sun for the goats) being my goat pen. and hoping to surround that goat pen with dedicated mulberry trees that the goats cant eat but when leaves fall they can enjoy some nice protien leaf fodder. Also goats and flocks should be able to bring in a decent portion of goods. Also i have some easter eggers i would likely try to run with the goats if i can manage a doable set up for chicken feed away from the goats. maybe some chicken pens and let them out as a daily chore but how to keep the goats from being a pain is also the question like always. As always i really enjoy your videos.

[@AKSnowbat907]

Had a thought, I was watching another video where they dug down about 10' through the clay and hit bed rock. Regardless of depth, having done the math if you dig a hole and brick up a 4'x4'x10' "well" calling it with a drainage grate with screen.. it could capture up to 1,200 gallons per re-well. If you add pipe as you brick up it will work like a septic tank with a leech field, just don't need a leech field, it'll leech. A French drain would be a nice addition to aid underground flow. We're talking the worst and driest areas.

[@kylegrandy498]

Im on 20 acres in northern California 16"-18" rainfall a year. Id like to put in a few swale on the bottom right portion of the property first pulling water from the main primary valley ( maybe giving a bit of fall on the swale to move water. I was advised 6'-8' wide 12" -18" deep. Delma cobbly loam quite sandy soil. Any input is appreciated

[@traceygraves2719]

Geoff, I love your teaching. You explain concepts so well. I would like some help please. I need a contact of someone in the Upper Blue Mountains to advise how to holdback and move water sitting on our property. Local people I’ve spoken to want to quickly take water away from the property. I would like to know how to use it but not have it water logging the property. Tracey

[@gabrielamora6265]

There is an example of a Farm in Australia where they kept the water logged marshland. Why do you want to remove the natural water retention system you already have? Many of the permaculture methods are aimed at recreating that type of feature. You might dig a few deeper ponds to get the water to concentrate more in certain areas.

[@pickles6425]

Question (timestamp 11:29): what tool can be used to "rip" the floor of a swale?

[@AntonioFCoelho]

Linda explicação!, a melhor de todas q já vi. Excelente didática

[@Zaidinetwork75]

Thanks for the sharings. Greeting from Malaysia

[@TheRegenBeacon]

Any explanations of why we don't graze the front slope of the swale? Are we just looking to avoid compaction/ diminution of the berm? It seems to me that if you are careful and only do it during drier periods that you would be able to moderately graze the berm of a swale safely without destroying it.

[@nataliemills6644]

Any suggestions as to what kind of trees to plant on the sown and back sides?

[@nessav7258]

You are a smart man and we can see the results

[@PoteetStrawberryville]

Benefiting Your Knowledge and Your Blessed Experience at Poteet, Texas Strawberryville Farm 👋🏼🍓👍🏼 01/11/22 08:58 CT Jose Dominguez Thanks G !

[@sparked3113]

Excellent presentation and info.

[@deanpd3402]

I actually did a course in earthmoving machinery after doing a course with Geoff. Takes a bit of doing to control those machines.

[@AlicedeTerre]

Oh wow I had no idea you can take courses in that. Makes sense

[@jaylightfoot3303]

Geoff, I live between San Antonio & Houston. I have 10 acres of sand, 5 feet deep before I hit clay. Water drains off very quickly. Will swales work in this type of soil? It doesn’t seem likely, in my mind...

[@suleymanpolat8487]

Look at Chinese desert works. Swales with some kind of spongy materials like hay or wood chips would work.

[@jaylightfoot3303]

@@suleymanpolat8487 I’ll do it. Thank you!

[@k.bellingham8335]

Just as all of the comments below I couldn't agree more with the high quality of your educational material, I too thank you very much for sharing your knowledge. I do have some questions if you have a moment, I notice a planting of bamboo in one of your examples. I have heard bamboo can be an invasive species. First, is this true? Second, if true how can and should these species be controlled if planted in a non-native location? The location I wonder about is an island in the Caribbean, quite dry with heavy rain events and washed by salty sea air, rocky poor quality sparse soils.

[@Нарангэрэлэнэхэнбэ]

Very comprehensive explanation/ Tank you sir.

[@ALIGHAZI]

so you said in dessert we should plant trees before the swales to prevent build up of salt, can you tell me what kind of trees can help in absorbtion of excess table salt and sulfur from water؟

[@mindsurfearth]

Hi Geoff, what is the steepest slope angle to still use swales?

[@louisegogel7973]

Lol I am guessing it depends on how you hold the swale together initially… before plants root themselves. I would think short bushy plants on really steep slopes would hold their position better.

[@peterking5372]

This is such great works

[@Unsolicitedbias]

I went on vacation once to Australia. It was such a long flight. I think I aged a year on that flight. When I got off the plane, I thought I had forgotten how to speak English. But it was just the Aussie dialect. But that was just the start of my problems. See I am a nature lover and I love the ocean. I can remember seeing a whale swim by my beach one day in Florida and I heard that Australia has some of the largest whale migrations anywhere. So I booked a flight and landed in Sidney. I cleared customs and hailed a cab. The driver was wearing some kind of head scarf or something and I could barely understand him. It sounded like he said, "Wheri too?". So I replied that I am here to watch whales. He drove me to the bus station and said I needed to get a ticket for Huttons Valee. I said great thinking that that would take me to the port for the Whale Watching cruises. We got to the bus station and I bought a ticket for Huttons Valee, and six hours later I arrived. I got off and immediated saw the sign for Permaculture and Swale and Water management. Sounded strange to me, but I walked up to the main house and asked for a room and if there were any whale tours tomorrow. The nice lady said, "Sure, it'll be ten dollars Australian for the room and after dinner if I liked I could go out and take a look at the swales in the evening. She said that it would be pretty seeing the bright orange sun setting to the west and a full moon would be up just a little after nine. I said great and took the room. Dinner was good, though they kept asking me if I liked the "tucker" and I said that I was not looking to get in trouble with anyone's girlfriend, just here to see the whales.

[@Andre-cg9xm]

I like your content. Antscanada introduced me to you. :)

[@patrickus2377]

Great info!!! Tell me if putting oxygen into the swale is a good idea or not needed. Thankyou

[@mrstratau6513]

How do you deal with mosquitoes in the swales?

[@ronnie2510]

Thank you for sharing this knowledge. Eye opener for me. But I have a question. Will not the percolation of water by using swales and contours increase the risk of landslides on slopes, especially in places where seasonal rains are heavy and soils are of loose type?

[@sherylpyers326]

The roots of the trees would help that eventually become less prone.

[@lindymccarthur2231]

Hi I live streaky bay, sa. I have around half acre . I want set up a self supporting food forest. Do you do consults?

[@skerriesrockart]

Fantastic info..thanks

[@kathlynblack3517]

Is it possible to have too many swales? I am working on a food forest development here in Texas. My growing area is approximately 80' x 80'. The property slopes down towards the back and is higher in the middle than on either side, front to back. I have dug 4 swales in the fruit tree area (the back 40'd x 80'w half), each contoured to the curve of the hill. They are small (about 12" - 18" across x 4" - 6" deep) and are about 90' - 100' long in a curve. I have 16 small fruit trees planted along those 4 swales and have made the banks hugelkultur mounds. The swales are only 8' - 10' apart at the widest points. Is that too many? They do hold back the water from rushing down hill and the soil has been improving. The ground does stay wetter longer than it use to. Is that too much? I don't want to rot out my trees. I have a clay based soil. Love your green movement, by the way!

[@Mindy56743]

I live in the ozarks and the land I have is mostly clay and rock. It is almost all a slope and I would love to do a 8 acre field with the swells and trees to see the effects we have about 46 inches of rainfall each year and usually we have a dry spell in July and August. Any idea how to start this.

[@arvinkim3037]

I live in an arid high desert climate in Southern California. How wide and deep should the sealed be. I have 10 acres of land

[@rataplanrrr]

Cheers, Geoff!

[@rodrigojaramillo8796]

muchas gracias, conocimiento que ha de ser compartido.

[@frechwieoskar8052]

I wonder since I first heard about swales what to do when I face cold air flow downhill and late frost events. With swales and the trees and shrubs on the mount or berm I would stop the airflow right? So on 600m and submontane climate probably a bigger problem than water shortage?

[@rolandpaterson9288]

We live on top of a disused shallow mine from the 1850’s. Therefore the soil has been churned and a lot of the topsoil has gone. We have a few acres of canopied 30yr old Eucalyptus. I’d like to install some swales. Do I remove the low value trees that are in the way or is there a better way to address the obstacles. Thanks

[@Goodtimes523]

Hi GEOFF! Can you address nitrogen fixation thanks!

[@vincent8344]

One or your best vidéo !

[@Darkfyre755]

What's about the steepest hillside you'd put swales into? And is there a better type of earthworks for steeper areas?

[@ibrewhaha]

I'm interested in swales to increase bamboo growth. Would this help? Comments?

[@elaineheeley3020]

I’m itching to get started with my Swales. Can you please explain to me what “on contour” means exactly?

[@AKSHATACJ]

@Discover Permaculture with Geoff Lawton Hi Geoff, 1. Buy land before taking PDC course 2. Take a PDC course and then buy a land ? Which one do you suggest and why ?

[@antoniodossantos5960]

Very useful information

[@Ray_Gelo]

In the tropical country like Philippines, how can we prevent mosquito from laying their eggs in the swale?

[@momentummv]

For a 10 acre flatland 140 X 300 meter squared, how wide and deep (in meters) should be the swales? Also What is the optimum distance between the swales in meters? Roughly how many swales should I have given that I get about 100 mm rain per year. Thank you.

[@jobotmang]

Thank you.

[@hansolex594]

Hi, i live in near the méditerranée and we have a huge mosquito problem. How to combine stagnant water and avoiding mosquitos ?

[@crpth1]

Fish and frogs, are usually the port of call for such an issue. Other than draining the stagnant water ponds/features! Notice that even an old car tire can be a source for mosquitos. So it's important to keep the landscape "clean". Look for gambusia, also commonly known as "mosquito fish! In Portugal we use them a lot in bodies of water prone to mosquito presence. They're, small, extremely efficient and resilient. Just check and DOUBLE CHECK, to not conflict with native species, if that's the case! By experience I can tell you that they're "nasty" hunters. In an aquarium environment, I saw a population of Neon's being wiped in a few days. By the, way more aggressive, gambusia! In spite of the similar size. Small lakes, ponds, open water well, etc. can be maintained mostly mosquito free in this simple way. No additional maintenance needed! ;-) Climate wise, Portugal is very similar to the Mediterranean. So development and survival of the gambusia is not an issue! Cheers