Posted: 24/12/2013 at 10:19
Making a new, unlined pond is the obvious answer to drainage problems. We did it as our garden would otherwise be waterlogged all year. Make it good and deep in the middle - 3' is good - and plant the edges with marginals such as iris sibirica and other irises plus some tall plants like miscanthus zebrinus which will mask the pond a bit when water levels recede in summer. As it is unlined you will need to referee as plants like yellow flag, bullrushes and native grasses will do their best to invade and terraform it so invest in some waders form a fishing supplies shop.
Since you can't do much else in winter, get to the lirary and borrow books on shade gardening. There are lots out there and an east facing garden should present plenty of opportunities for beautiful and interesting plants. Wildlife doesn't need native plants so much as plants which provide pollen, nectar and shelter. You can also consult the RHS Plant Selector for plants suitable for an east facing garden - http://apps.rhs.org.uk/plantselector/
With a new and unknown garden it's also a good idea to let it be in its first year and just weed borders, cut tehgrass and do obvious pruning. Then you can see what you have and what you need to change. Take photos and jot down ideas as they occur so that, come autumn, you can start the planning and design of all the changes you want to make. You can also sow seeds and bring on new perennials for planting out later on.