New pond - size and location help please

What sort of pond are you contemplating, glasgowdan, formal, informal, wildlife, raised, etc? I would recommend using a butyl liner rather than a preformed pond. Do you plan to put fish in the pond? Being in a Southern position you will need a depth of around 2 feet, or more, so that the water doesn't heat up too much and lose oxygen. Also you will need to plant marginal and oxygenating plants to take up excess nutrients in the water to help prevent algae forming and clouding the water. If you do want to plant marginal plants then it will help if you dig shelves three quarters of the way around to put the pots or small crates holding the plants on. The shelves would need to be about 10 inches deep and wide enough to sit the pots/small crates on.

 

Well, believe it or not, but a wildlife pond will take, say, 3 or 4 Goldfish and they don't really need looking after. I have about 6 fish in my wildlife pond, which I dug in '93, and they survive happily by themselves without me feeding them. There's also Frogs, Newts, etc that permanently reside in and around the pond. Insects like Water Boatmen will come and live there feeding off other insects, all that happens over time as the pond matures.
My pond is about 12' by 22' and runs to about 3' 6" in depth with a shallow end to let any wildlife get out. I used Butyl liner and, as Tetters said, don't cut corners on the quality of it, so get a liner with at least a 30 year guarantee. The pond is, like yours will be, facing South but unlike yours is in a light shady position.

A bench by the side of the pond to sit and watch the wildlife




You can see what has developed since '93. Now, I'm not saying your pool should look anything like mine, but just showing what a hole in the ground can be turned into.

 

Well, some Garden Centers sell Marginal and oxygenating plants, and some don't but there will be some in your area that do. You need both to give shelter to wildlife and also to take out excess nutrients out the water and they use those nutrients to grow.

Well, not unless you get flocks of them, which I doubt will happen. Bird poo dropped into the pond will only add nutrients and will be taken up by the marginal plants. Birds will use the pond to drink from though.

Firstly, to make a wildlife pond look natural you can lay grass along the edges as I have which takes nicely. I've put large stones on the edges as well and there should be no need for mortar as the weight of the stones will keep them in place, note that I said stones...not pebbles.
There a quite a few plants you can use as marginal plants such as Marsh Marigolds, Yellow Flag Iris, Iris Versicolour, Lythrum, Pontederia, etc. Have a look around, do a little research on them and find what you think is right for you.
Planting marginals is best done using large pots and/or small plastic crates with holes in the sides

You don't need special soil, just use the garden soil. But you will need some hessian sacking to line the crates to keep the soil in. Plant the marginal plants in the soil and then cover the soil with gravel to stop it floating out, and then if your shelves are deep enough you should be able to cover the pots/crates with about 2 inches of water. One thing that happens with new ponds is that marginals are planted thinly and there aren't enough of them to take all the nutrients out of the water and algae appears. You don't have to buy a huge amount all at once but just keep adding them until you have enough for the pond to maintain it's own balance.
If you've got Kids then you need to be watchful as accidents do happen so kids should never be left alone near a pond. I had 3 young daughters who brought their friends home, so I built a fence around the pond with a lockable gate. That was followed by a Jasmine and Clematis hedge to hide the pond from the rest of the garden to make it a place to sit out of sight.
Anyway, build the pond in the style that you want, take your time and enjoy it. So long as you understand what the pond needs to keep it in balance then maintenance will be minimal and the wildlife will come.

 

One or two plants for you to consider, glasgowdan

"With the extensive range of pond plants available in nurseries and garden centres, selecting the right plants can be daunting. The vigour of the plants and avoidance of unwanted invasive types as well as the suitability in varying depths needs to be taken into consideration.


Suitable plants


Choose plants that give contrasts in foliage as well as variation in flowering times to give as long a display as possible. The following list gives a selection of plants that garden centres, nurseries and pond plant specialists are likely to stock.

Submerged plants (aka oxygenators)
Submerged plants produce oxygen during the day and provide cover for aquatic life

Callitriche hermaphroditica (syn. C. autumnalis) (water starwort): Also suitable for running water (may become too invasive for small pools)
Ceratophyllum demersum, C. submersum (hornwort): Suitable for deep water, free floating
Fontinalis antipyretica (willow moss): Best planted attached to a stone, suitable for running water
Groenlandia densa (syn. Potamogeton densus) (frog’s lettuce)
Hippuris vulgaris (mare’s-tail)
Hottonia palustris (water violet): Do not move or plant in summer; lilac flowers in summer
Myriophyllum spicatum, M. verticillatum (water milfoils)
Lobelia dortmanna (water lobelia): Pale violet-blue flowers (may become too invasive for small pools
Potamogeton crispus, P. pectinatus (may become too invasive for small pools)
Ranunculus aquatilis (water crowfoot): White flowers in May; also suitable for running water

Floating plants
Floating plants do not need anchorage in soil. Their presence on the surface reduces the amount of sunlight penetrating the water and keeps the water cooler, discouraging algae. Aim to keep around 50% of the surface clear of vegetation, if necessary by thinning occasionally during the summer.

Azolla mexicana: Severe winters may kill this plant. Leaves turn reddish in autumn (may become too invasive for small pools)
Hydrocharis morsus-ranae (frogbit): Small white flowers; sinks to the bottom in winter
Stratiotes aloides (water soldier): Floats just below surface; sinks in winter (may become too invasive for small pools)

1. Water 30cm (1ft) or more

Alisma plantago-aquatica (great water plantain): White flowers. Remove dead flowers to prevent seeding. Height 60-90cm (2-3ft) (may become too invasive for small pools)
Aponogeton distachyos (water hawthorn): Tuberous. Fragrant white flowers. Water snails will feed on this plant and kill it. Height 5cm (2in)

2. Water 15-30cm (6in-1ft) deep

Menyanthes trifoliata (bog bean): Olive-green trefoil leaves, pinkish white flowers in spring. Height 15cm (6in
Ranunculus flammula (spearwort): Bright yellow flowers. Height 70cms (2ft 4in)
Thalia dealbata: Bold blue-green leaves. Height 1.5m (5ft)
Zantedeschia aethiopica (arum lily) AGM: White spathe, golden spadix, fragrant. ‘Crowborough’ is the hardiest form. Height 45cm (1½ft)

3. Water 5-15cm (2-6in)

Acorus calamus ‘Argenteostriatus’ (sweet flag): Foliage variegated creamy-white, greenish flowers, can be invasive. Height 60cm (2ft) (may become too invasive for small pools)
Butomus umbellatus AGM (flowering rush): Pink flowers in summer, like a miniature agapanthus. Height 60-75cm (2-2½ft)
Calla palustris (bog arum): Glossy leaves, white flowers in summer, followed by spikes of red berries. Height 22cm (9in)
Glyceria maxima var. variegata: Yellow and white variegated leaves, rosy autumn leaf colour. Height 60cm (2ft) (may become too invasive for small pools)
Iris laevigata AGM: Rich blue flowers in June. Height 60-75cm (2-2½ft)
I. pseudacorus AGM (yellow flag): Yellow flowers. Height 90cm (3ft) (may become too invasive for small pools)
Juncus effusus f. spiralis (corkscrew rush): Stems twisted in a corkscrew manner. Height 45cm (1½ft)
Lobelia cardinalis AGM: Purplish foliage, scarlet flowers. Needs winter frost protection in most regions. Height 60-75cm (2-2½ft)
Lysichiton camtschatcensis AGM: white flowers. Height 30cm (1ft)
Orontium aquaticum (golden club): Shiny leaves, yellow flowers in a spike. Height 10-12.5cm (4-5in)
Pontederia cordata AGM (pickerel weed): Glossy leaves, blue flowers in late summer. Height 45-60cm (1½ft-2ft)
Ranunculus lingua ‘Grandiflorus’ (giant water buttercup): Reddish stems, large yellow buttercup flowers. Height 1.2m-1.5m (4–5ft)
Sagittaria latifolia: White flowers in late summer, autumn foliage colour. Height 30-90cm (1-3ft) (may become too invasive for small pools)
S. sagittifolia ‘Flore Pleno’: Double white flowers. Height 75cm (2½ft)
Schoenoplectus lacustris subsp. tabernaemontani ‘Albescens’: Stems sulphur white when young, darkening to green. Height 1.2m-1.5m (4-5ft) (may become too invasive for small pools)
S. lacustris subsp. tabernaemontani ‘Zebrinus’ (zebra rush): White stems banded with green. Height 45cm-1.2m (1½-4ft)
Typha angustifolia: ‘Cat’s tails’ inflorescence. Height 1.2m (4ft) (may become too invasive for small pools)
T. laxmannii: Narrow leaves, ‘cat’s tails’ inflorescence. Height 90-1.2m (3-4ft)
T. minima: Brown ‘cat’s tails’ inflorescence. Height 30-45cm (1-1½ft)

4. Very shallow water (less than 5cm [2in] and mud)

Acorus gramineus ‘Variegatus’: Leaves striped pale yellow. Height 20-30cm (8in-1ft)
A. gramineus var. pusillus: Forms dense tufts. Height 7.5-10cm (3-4in)
Caltha palustris AGM (marsh marigold): Large golden flowers in March. Height 22.5-30cm (9in-1ft)
Carex elata ‘Aurea’ AGM (Bowles’ golden sedge): Golden foliage. Height 45cm (1½ft)
Carex pendula: Arching stems, drooping brownish spikelets. Height 90cm-1.2m (3-4ft)
C. pseudocyperus: Bright green foliage, dark green spikelets. Height 60-90cm (2-3ft)
Cotula coronopifolia (golden buttons): Annual, sometimes perennial, seeds freely, aromatic foliage, button shaped yellow flowers. Height 15cm (6in)
Houttuynia cordata: Dark green leaves, red stems, white flowers. Height 60cm (2ft) spreads freely. ‘Chameleon’ leaves variegated red and yellow (may become too invasive for small pools)
Iris ensata AGM (Japanese water iris): Blue, red or white flowers. Height 60-90cm (2-3ft)
Iris sibirica AGM: Blue flowers. Height 45cms (1½ft)
Iris versicolor AGM: Violet-blue flowers. Height 60cms (2ft)
Mimulus cardinalis AGM: Orange-red flowers in summer. Needs winter frost protection in most regions. Height 30-45cm (1-1½ft)
M. lewisii AGM: Red or white flowers. Height 30-60cm (1-2ft)
M. luteus: Yellow flowers. Height 30-45cm (1-1½ft)
M. ringens: Violet-blue flowers. Height 45-60cm (1½-2ft)
Myosotis scorpioides (water forget-me-not): Blue flowers in May. Height 23cm (9in)
Saururus cernuus (lizard’s tail): Fragrant white flowers, dark green leaves. Height 15cm (6in)
Veronica beccabunga (brooklime): White-centred blue flowers. Height 10cm (4in)

 

I agree, a wildlife pond is natural looking and will blend in better with the garden and Nature is definitely not a Pristine Entity.

 

I followed the late great Geoff Hamilton's advice when digging out the pond by incorporating a Bog Garden into the pond. He recommended putting the liner in, then laying a dry brick wall into the pond along the length and about 6' from the bank. He then advised using ordinary garden soil to fill in the space between the dry brick wall and the bank and then fill the pond with the water. The water then seeps between the gaps in the brick wall to feed the Bog Garden and keep it moist. I did that and it has worked nicely, with the bonus of the Bog Garden plants also helping to keep the pond water clear by extracting nutrients from it along with the Marginal plants.