Powered By Blogger

13 February 2021

The Pond, and end of the project - at least for now

Portia Widow - one of 10 dragonfly species we have photographed!

The pond, the primary goal of the entire project was actually completed a few months ago already. However, ponds take time to develop life, and much of the surrounding reeds, grass and sedges have taken a little while to establish themselves.

Starting the 'big dig' in mid-November was not the greatest plan. The summer rains were in full swing already, and given the clay content of my soil - it could only mean sludgy mud was inevitable. On a normal day, clay soil is actually quite easy to dig through, far better than stony top soil at any rate. Wet clay soil is also easy to dig through, but that is where the similarities end. One's spade gets stuck, you have to pry the gloop away from the surrounds, its heavy to lift and gets stuck to the inside of a wheelbarrow. After a few loads, you end up 'growing' 2-3 inches as your boots accumulate extra layers underfoot - its thoroughly unpleasant. All this 'work' was voluntary of course, I could have binned the project for the winter at any time - but it gave me pause to think of what those on either side of the Battle of Passchendaele had to live and fight in, for months...

For the better part of three weeks, I'd go outside for an hour or two most afternoons and dig another section. At times I spent half the weekend digging and carting tons of clay out of the hole. The hole progressed fairly well until the 7m mark where a significant rock stratum was discovered. Ultimately, there was little choice but to rework the pond according to this rock layer - we would now have a deep section of 7 metres, a sloping incline of 4 metres and a shallow area of 2 metres. This would work just fine as it happened - the shallow section would get some sedges planted and be the perfect sanctuary for fry and tadpoles. By the time that digging itself had ended, I calculated that a total of 10.5m³ of clay soil had been moved by spade and wheelbarrow - which equates to a shade under 20 tons.

The rain increased in volume steadily over the first weeks of December, culminating in a single downpour that filled the mud hole in less than 20 minutes! With the end in sight, I dedicated a full weekend to finishing the pond. Firstly I needed to install a home made filtration system - an old metal bath that would be counter sunk to one end of the pond and filled with gravel, rock and coarse sand. Then it was a case of pumping out all the rain water to fully empty the pond and dump 20 odd wheelbarrow loads of grass cuttings to line the pond before we could unfurl the 15 metre long plastic liner.

A little plastic liner wrangling was necessary as Kaily and I fought the wind to get the plastic into the pond, before we checked alignment and began filling. The pond would hold just over 10 000 litres of water - about 5 average JoJo tanks worth. We didn't have that much water stored, so we planned to put in around 2 000 litres just to keep the plastic in place, we'd let the rain do the rest. It was a long wait - as the last few weeks of December saw little to no rain... Finally, in early January 2021, the pond over flowed for the first time and has maintained a full to overflowing position ever since. A number of sedges have been planted, the volume of tadpoles has exploded and only a week ago we released 3 young Largemouth Bass into the pond. The bass are far from native species - but they will do the job of maintaining carnivorous order until we can find some native Tilapia species to take over.

Would I spend another 4 months of my life digging marshes and ponds? Absolutely. They have brought a plethora of new life to this once dull and stagnant property - life that keeps us gloriously entertained day or night. Indeed, the pond and marshes have brought another dimension to our appreciation for wildlife, as we have now gotten into 'dragonflying'... Meg, Kai and I have spent a few afternoon snapping away at the various species, having already photographed 10 different species, with at least a further 2 having eluded our lenses so far.

1.   Broad Scarlet
2.   Common Citril
3.   Eastern Blacktail
4.   Jaunty Dropwing
5.   Julia Skimmer
6.   Nomad
7.   Portia Widow
8.   Red-veined Dropwing
9.   Smoky Spreadwing
10. Swamp Bluet

A few days in, only about 1.5m³ 

Digging needed to be done in steps.

Drain, dig, then drain some more...
The muddy gloop at its zenith

20 minute downpour from an afternoon thundershower

Lined with grass cuttings

Kai and dad - almost done (and the bath filter system)

15metres of plastic - its longer than you think!

The initial fill and grass sod lining

How things look today

The marshes and pond - left to grow wild!

Broad Scarlet

Common Citril

Eastern Blacktail

Jaunty Dropwing

Julia Skimmer


Red-veined Dropwing

Smoky Spreadwing

Swamp Bluet

19 January 2021

Marsh 3 and new life!

Common River Frog

Dig number 3 would be another shallow endeavour dedicated to increasing the marsh space. At 10m long and more than 2m wide, this would be the largest of the marshes for this project, at least for now. With only around 20cm of topsoil to move, the dig was fairly straight forward - taking Kai and I a little more than 3 days. For perspective, the volume of soil removed was around 4.4cubic metres, and given it was quite compact - was estimated to weigh around 7 tonnes, 1 wheelbarrow at a time...

With the hole dug quickly, we had one bit of trouble - we were short on grass clippings that I planned to use as a buffer between the bare earth and the plastic liner. So we needed another afternoon to cut the lawn and get the hole prepared first. In went the plastic liner, followed by some course sand and a few sods of earth to keep the plastic from blowing away. Rain wasn't predicted for a few days, so to speed up the filling process a little - we emptied around 1000 litres of water into the marsh from our JoJo tank.

Filling the marsh with marsh plants on the other hand was going to take a rather monumental effort. Based on the number of truck loads needed to fill the already completed second marsh, I was looking at the prospect of needing nearly 20 truck loads of plants! That wouldn't work, so instead I lined the border with marsh plants whilst filling the inner section with sods of grass and earth - the flufftails and crakes would need some muddy patches to hunt for earthworms and other invertebrates.

The grass either side of the marsh itself would be allowed to grow at will, providing more cover for birds, amphibians and insects. Indeed, within a week of the pond being filled and the first vegetation planted - we had our first dragonflies, numbers that would increase from a mere handful to well over 50 individuals at any one time (species ID to follow one day...). The previously 'devoid of life, nothing but lawn' property had now seen a sudden spike in the amphibian population too, increasing from just one species of toad when we moved in, to at least 6 species that I could readily identify, I'm sure there are one or two more that I am missing. 

1. Gray's Stream Frog
2. Common River Frog
3. Natal Spiny Reed Frog
4. Painted Reed Frog
5. Guttural Toad
6. Snoring Puddle Frog

Post Ed: Birds have started to make use of the pond in decent numbers, with Hadada Ibis bathing every day, Bronze and Red-backed Mannikins drinking and devouring the seeding grass, and even the skulking Burchell's Coucal snagging large insects on his way through the morass.

Basic layout  - with Marshes 1 & 2 in the background.

Border grass removed, to be used later to hold plastic liner down.

Final depth was a little over 20cm deep

Grass clippings for cushioning between earth and plastic liner.

Course river sand and grass sod for weigh.

Border lined with marsh plants.

Open water and marsh edge for dragonflies and amphibians.

Growth increasing quickly.

Painted Reed Frog calling loudly

Gray's Stream Frog (Clicking)

Natal Spiny Reed Frog

11 January 2021

Marsh 2

Marsh 2 was always planned to be shallow and full of dense marsh vegetation. With similar dimensions to Marsh 1, this hole would add little in terms of water volume, but produce 6m² of good marsh habitat.

Long term, our plan is to entice Black Crake and perhaps even a young Red-chested Flufftail to take up residence. They both require similar habitats, patches of dense cover, water edge and foraging areas of mud or short vegetation. Whilst only a small patch to start with, this again would be the testing ground for the much larger ‘Marsh 3’ to come.

Digging commenced on a Sunday, removing the grass layer to expose a small volume of topsoil over the much deeper clay. With a target depth of only 20cm, digging didn’t take long – indeed, only a few hours of labour were required late on Monday afternoon to finish the job. Grass trimmings added, the plastic sheeting was laid a few minutes later. Some helpful evening rain even filled the marsh ahead of marsh plant collection.

Despite its small size, filling the pond with the requisite marsh plants, mud and other aquatic wildlife took 6 trips to various locations. To keep my impact down to a minimum, I collected material from degraded or heavily disturbed seeps and drainage ditches within the area during the late Autumn, before the growing season had started.

Post Ed – a few months after planting and the increased rainfall, light hours and temperatures have spurred on growth. The marsh is now exactly as intended with plentiful cover and an ever-increasing density of frogs, insects and other invertebrates.

Initial grass clearance - not much topsoil here!

Plastic lining went on quickly with a few logs to hold things in place

Even drizzle flowing from roof to marsh.

A day after lining and the mrsh was already full of water

First marsh plants added.

Multiple trips later, still not fully vegetated.

Two months later - the marsh was growing fast.

A heavy downpour showing the growth of Marsh 2 and the beginnings of pond 1 in the background.

4 January 2021

Manufacturing a wetland

When I was about 14, I convinced my parents to let me run riot in their garden. I chopped out all the exotic rubbish, replanted with indigenous and even put in a small pond (made with a piece of orange roofing plastic that my old man found for me somewhere…). Since then, I’ve always wanted a grander dam or lake in my backyard, but never lived anywhere long enough to make it happen.

Fast forward around 25 years and I found myself buying a property with Meg. I looked at the backyard and saw my chance. Fairly flat ground with only a vegetable garden and a lot of lawn to conquer. In the days before COVID, I imagined hiring a backhoe and digging one ginormous pond to house Large-mouthed Bass in order that I could go fishing in my own backyard… So, we moved the veg patch and enclosed it, got rid of a rudimentary rockery and built a fine BBQ area in its place. All I had to do was get working on the lake.

By the time I finished sorting our all the other upgrades and renovations around the house, COVID had arrived and lockdown was in full swing. Not only was the backhoe idea out, so was the ginormous pond for fishing - an alternate outcome was required, one that was going to cost very little and surely involve a rather large amount of personal labour… Back to the old days it was then, self-dug holes and plastic liners would be the order of the day. Since long and wide liners cost a small fortune, I planned to use smaller sheets of plastic that are more routinely used in roofing to provide under tile waterproofing. At 250um thick, they should do the trick. My intentions had changed somewhat too, out with the big fishing pond and in with a number of shallower marshes for amphibians, crakes and flufftails.

One afternoon with 'lockdown beverages' in hand, Meg and I arranged a pile of soda bottles, plant pots and hockey sticks around the backyard to form a basis for the grand scheme. A few days later, we started laying the main water feeder pipe – a 50mm ldpe pipe connected to our JoJo overflow. Trenching and pipe laying done, a multitude of connections were fixed and laid, ready to fill all the ponds and marshes.

Phase one would be a small pond – something that would allow us to test form and function. Early on a Saturday morning, Kaily and I headed outside with spades, shovels and wheelbarrows. The first hole was scheduled to be 3 metres long, 1.7metres wide and around 40 centimetres deep. 5 hours and 36 wheelbarrow loads of dirt later, we had our first hole. To provide some protection, we tipped in a few piles of old cut grass and laid the plastic. In went some water from the JoJo to get things going, before the evenings predicted rain arrived and proved that our piping worked too. Now we needed some life, so we hit a nearby marsh for some reeds, before another downpour the following day filled the pond. In the space of a week, we had increased our water capacity by 2000 litres and breathed some new life into what was the sterile lawn. 

*Postscript. Marsh 1 would indeed be the practice run, for we could not keep the water oxygenated enough. We ended up filling the pond in with soil from Pond 1 to create a contiguous marsh. Successfully punctured the lining and had to re-dig it and re-line it…

Planning - with soda bottles and hockey sticks

Feeder pipe form the JoJo overflow 

Breaking ground

Almost done

Black liner with first water going in

Almost complete

There was a leak somewhere, but it was a case of digging it out again

Re-lined and filled