She was found at Manor Park in Aldershot, and police are urging her mum to come forward to get help.
Hampshire Beaches Praised
Several beaches on the South Coast have been given the top award for water quality in the latest Good Beach Guide.
22 in Hampshire and the Isle of Wight have been recommended as safe for swimming, and 8 in West Sussex.
Isle of Wight
Colwell Bay Gurnard
Sandown - Yaverland Sandown Shanklin
Southsea (300m West of EC Site)
Old Portsmouth Beach (Victoria pier)
Bognor Regis (Aldwick)
Bognor Regis - East
But the Marine Conservation Society (MCS) has warned the kind of heavy rains which have hit in the past week are bad news for the country's beaches, washing raw sewage from overflow pipes and pollution from towns and rural areas to bathing areas.
The group's latest Good Beach Guide also reveals areas which are not successfully tackling poor water quality, among those once again failing to reach mandatory levels for clean water.
The results of the latest guide, based on testing carried out last summer, show that 516 out of 754 UK beaches were recommended for ''excellent'' water quality - more than two-thirds (68%) of the total number of bathing spots.
The results show an 8% rise in the number of beaches getting the best grade on the previous year's figures and is the best set of results in 25 years of the guide.
But 25 beaches failed to achieve even the mandatory levels of water cleanliness.
With the first measurements being taken this summer under new, more stringent European Union water quality rules which come in in 2015, the MCS is warning against complacency over improving standards.
Coastal pollution officer Rachel Wyatt said:
''It's really important that local authorities, water companies and environmental regulators don't become complacent and take their collective feet off the pedal of continued environmental improvements.
''If that happens we could see a drop in the number of beaches recommended by us in the future, which could pose a risk to the great reputation British beaches have.''
One of the major threats to bathing water quality is overflow pipes which discharge raw sewage into rivers and the sea from sewer networks when heavy rain overloads the system with water from street drains.
The MCS has previously revealed there are about 31,000 of these ''combined sewer overflows'' around the country, more than three-quarters of which are not monitored to see how often they are discharging polluted water.
The conservation society is concerned that some of them are discharging untreated sewage dozens or even hundreds of times a year, far in excess of guideline levels.
MCS pollution programme manager Robert Keirle said:
''Combined sewer overflows are an essential part of a well-maintained sewerage network. If you didn't have them in times of flood sewage would be backing up in our toilets and manhole covers in the street.
''What we are worried about is them being used too frequently by water companies as a matter of routine, not just emergencies.''
He called for monitoring of all the overflow pipes around the country in order to find out how often they were discharging polluted water so steps could be taken to manage them.
The other risk to bathing waters caused by heavy rain is diffuse pollution washed into rivers and coastal areas from the countryside and towns as a result of downpours.
Mr Keirle said urban residents could reduce pollution by cleaning up after dogs, to prevent them fouling in the streets which can then be washed into the river system.
Putting buffer strips of vegetation between fields and rivers and keeping livestock fenced away from water courses in the countryside could cut the risk of manure washing downstream and polluting waters where people want to swim, he said.
Find out all the recommended beaches on the South Coast by clicking here .
It'll open this September and handle customer service calls for big names like Argos, B&Q, Monsoon and Wickes.
Flights at London City will be directed remotely, 80 miles away at Nats in Swanwick from 2019.
AET wants to merge its Sandown Bay and Ryde academies, saying it can't afford to run both.
Recently Played Tracks
Now playing: The best feel good music
Deposit £10 to get a £40 Welcome Bonus - That's £50 to play bingo, slots and more!*
Over 50 tracks to make you feel-good. New album out now...
Find your local four day weather report here.
What's happening on the roads where you are?
Make Heart the soundtrack to your day and you could be a winner with great prizes up for grabs throughout the day.
Find out more about some of the companies advertising on Heart.
Get some great ideas on how to advertise your business on radio, online and on mobile.