I've worked predominantly in the environmental engineering field - contaminated land (mainly GIS mapping) and ecological/geological surveying.
There's intense competition for full-time secure positions in the environmental engineering field. There are a few more opportunities for example, in ecological surveying, during the spring/summer time, which for obvious reasons tend to be the best time to conduct ecological surveys.
A major problem with this field of work is travelling. There can be a lot of it and regardless to whether I work through an agency or employed directly by a company, I will be expected to travel. The work is also rather sparse since there's usually more surveyors than survey work - this certainly was the case in 2000-2004 which leads on to another concern.
My concern: I can see things getting worse because of the current economic climate. A major employer of ecological/geological surveyors is the construction industry - an industry which is on the brink of collapse due to the credit crunch. One major construction company has already ceased all house building projects and I'm sure many more building firms will follow. If there is competition for jobs in a downward market, I doubt they'll employ the one whose just return from a career break!
I've mentioned change of career because during the last 4 years I have embarked upon an Open University course. I did really well at the first level, gaining a distinction, but then failed/dropped out of a level 2 course because it was difficult, boring and the exam was only a couple of months after I had given birth to ds and I could not prepare/revise enough to pass the exam. Nevertheless, I'm considering continuing with the course which is in social care. This course would open up opportunities in social work which are more likely to be local - or am I being naive? I've met many social workers and they told me they rarely, if ever, left the county unless it's for conferences and such like.
The downside is that I haven't done much research on social work or what it is like to be a social worker or what are the employment prospects. I've often heard that there are not enough social workers but there's likely to be a reason for this!
I think for the meantime, I'll go back to what I know best, which is the environmental engineering field. I've attended CPD courses during the last 4 years and kept my skills up to date. I'll just have to wait and see what happens.