Please help me decide on earthworks plan. Less irrigation, more food. Tough climate. Ideas?

Semi arid climate, typical hot drought summers, snowy wet winters. Best techniques of growing most food with minimal irrigation?

Hey y'all. I've got a site in central Washington, about 20" precip per year with most precipitation from October-March consisting of snow, which then melts and the weather turns very hot and dry throughout the summer, including high wildfire risks. The site has a slight slope down toward a creek about 400 feet away. I'm trying to grow fruit/nut/native trees/shrubs and staple vegetables like corn, potatoes, beans, and squash. High calorie foods. But, I want to do it with minimal irrigation, ideally none.

Question is, with this section of land, would you recommend one of the following:

a) rent an expensive excavator, gather tons of logs, and make giant hugelkulturs on contour
b) hand dig swales, fill them up to just about ground level with logs and brush, then cover with soil to act as natural berms, then plant into those with trees/shrubs
b) dig swales on contour, but plant things within the swales rather than on the berms because the climate is so dry and so sunken beds would actually be more beneficial
c) dig swales, plant trees on the downhill slopes of the swales, then with the 15 feet between the swales plant vegetable crops and bite the bullet and run drip irrigation to them
d) dig swales, plant trees on the downhill slopes of the swales, then run chicken/rabbit tractors between the swales until eventually the soil is so rich you can dry farm veggies in between the swales
e) rent expensive excavator, and without previous experience doing so although many hours spent reading and watching youtube videos on the subject, try to dig pond on south side of these hugelkulturs/swales/etc.
f) something else

Open to any and all ideas. Here's a drawing of the landscape. Extra info: I've water dowsed and got readings of potential water underground going through these dotted lines on the land. Previous land owner said they had two water dowsers out who both said there was a large underground spring in that southeastern line specifically. Haven't found much indicator plants for this yet, other than wild ancient apple tree along road that is one of few areas not previously mowed (i've only been here one year). Also, my drinking water is currently heavily filtered due to extreme iron amounts. Having a better source of water is of interest. IDEAS IDEAS IDEAS WHO'S GOT EM??

I don’t grow in the same climate, since we are far south, but we don’t get any water from May to November. We do have irrigation, but it’s drip only. The drip lines and below the soil and or mulch, to prevent evaporation.
During the hottest months (July to October) we get up to 120F. My plants survive because we use shade cloths to protect them.
You can harvest water from the air, by digging a hole and cover it with a funnel. The temperature in the soil will always be lower than up in the air. This causes evaporation to form on the side of the funnel, and drip down into the whole. You will be surprised about just how much water you can get that way.
You can use this system for annuals in the summer too. You can buy a set where you dig the bucket down, and add water wicks. Then add the lid, and you probably won’t have to water them again. It doesn’t work for trees, since they grow too big for the bucket and you then can’t get it out. This stunt the growth of the tree. They use this method in de deserts but use compostable buckets, so they don’t have to remove when the trees get too large.
Snow is water, so find some cheap large barrels and fill them with snow during the winter. Once spring and summer arrives, the snow will melt and you have water to use.

Rather than renting expensive equipment, why not spend that time and expensive working towards building soil health to conserve on water?

Some tips:

Some easy ways to get started would be to get wood chips and fall leaves.  Use these to make compost and mulch.

Start planning your garden with drought resistant plants.

Do you do rainwater harvesting?

Get into the habit of using mulch to conserve water.

If snow is going to be your primary source of annual precipitation, I'd like to know what your prevailing winds are too, since this will determine whether the snow is likely to collect or be blown away from swales on contour. From what you say planting in the swales is likely to be most successful, but your climate doesn't sound that dissimilar to Paul Wheaton's in Montana, and he swears by huge huglekultur berms.
As you say, the aerial photo doesn't show much sign of water in either of the potential spring areas, so the spring, if there, is not accessible at the moment by the vegetation. It could be deeper down, or covered by a clay or rock layer perhaps, that is preventing the plant roots accessing it.
Do you have access to the creek and does hat run year round? If you are, then running water can provide a "ram pump" action and deliver water to a reasonable height with no power requirements. A Little thread about them here

I'd say one of the key observations to make in your first year in a new locale is:  what are other people successfully growing in your immediate surroundings, and up to maybe a 10-20 mile radius given that you are in pretty sparse open country? And in what kind of circumstances - i.e. terrain/slope/aspect, irrigation and hydrology, mechanical aids (tractor work), 'guild' structure (if any)?

When you start planting, invevitably some things will work and others won't, but in challenging unfamiliar circumstances it's nice to know at least a few of your experiments are likely to succeed, based on what is already demonstrably working for others nearby! Corollary to that is start with smaller scale trials to see what you can accomplish, before throwing lots of effort and resources into misguided schemes that just don't work. Nobody can tell you with confidence what's best for your site, unless they've done it there before.

As someone currently working in a relatively similar, slightly warmer climate, ponds are far from ideal for seasonal storage unless carefully lined and capped to reduce summer losses, unless you have a steady spring source to replenish. Better to think about enclosed cistern system to supplement during early establishment years and during drought spells.

Sean,

The best approach would be if you planted all the vegetables you want to grow and observe how they deal with your climate throughout the year. Then you would start having an idea where to apply what kind of improvements.
For example - I irrigate and mulch everything and it fails (especially vegetables), because it's too hot in summer and the mountain sun is way too intense, so this year I will be focusing on shading.

Sean, there are some great ideas already presented.
I have a few questions;
- what size is your site?
- What soil types do you have?
- what skills do you have?
- Why hire expensive equipment, hire equipment that will do the job.
- Do you have a budget?
Anne asked about rainwater harvesting, I do a lot of work in that area.
But I dont normally deal  with snow, so I need to learn about that.
Rain can be captured on a roof and stored in a 20,000L tank, not a 200L barrel for realistic water catchment.

You wait for the snow to melt and then capture it in a large tank.