What does this temporary lake, formed from winter rains, look like in
color, size, wildlife around, during the day and during the night?  Is
there wind, or is it smooth most of the time?  What color is it at
night when the moon shines on it (and when it doesn't)  What is the
daytime temperature, and the nighttime temperature?  I assume kids
could go swimming there at midnight? From pictures I see small bushes
or shrubs at the sight.  What kind are they and how large are there? I
am writing a children's story for publication, so the info needs to be
highly reliable and accurate. Thanks, Teacher Janice

I dont think the lake would be there during summer .. specially in
riyadh ..  u can say riyadh is part of the desert .. and swimming is
not recommended , as swimming pools are available free for men .. I
had never been there but this is what I think according to my 19 years
in saudi arabia ..

free comment ;-)

Teacher Janice,
This is a general comment about "temporary lakes in saudi deserts
formed during winter".

I'm from Saudi. These are actully not called lakes but "Fithah" in
Arabic which means somthing like a temporary Oaises that forms during
the rainy season.

They mostly dry off by June-July. 

Depending on the depth and size, the water can be clear or merky.
Nobody uses it for drinking nowdays. There is usually plenty of birds
(local and migrating) but not in flocks.

A few people can swim because of the mostly cold weather. And a few
drown every year (mostly kids who dont know how to swim).

In winter: Desert temps can differ by 10-20 deg C in in the winter,
going close to freezing sometimes in the night, but can get nice and
worm in the day.

Usually people camp around these Faithah's during the first months of the year.

In my opinion they are a romantic and peacful place away from the buzz of the city.

Regards,
Zrenegade

P.S. You said you need this info for a children's story. Can you give
me more info and I will try to provide you with some more sources.
It's pleasent to see people writing "Nice" things about my county.