House Martins nesting

We are lucky enough to have had housemartins nesting on our house for many years. More recently the number of nests has dwindled down from 17 nests to 6 or 7.

A lot of this seems due to the lack of mud for nest repair and rebuilding, it's been very dry and there is no mud nearby. We tried some man-made ones which have some success, but the birds clearly prefer self-builds!

This year arrivals were very late again, but we have up to 20 birds swooping round the house anxious to breed

In desperation, as there is no mud, we have run a hose on the track to our property to soak a small area, and within a few minutes a flurry of excited birds started mud gathering. Great!

But, with no sign of rain in the next few days, and having given them a start, I now feel duty bound to keep watering every half-hour so they can continue their work.

Does anyone have an ideas to help and make the process easier???

I cannot really create a pond or wet area in my garden, so it needs to be on the public track.

Thanks

p.s. we have also seen buzzards, red kite, marsh harrier and the other day, a hen harrier so far this year