How badly do you want to fix this? It is fixable, but be prepared for a long battle.
First of all a few clarifications? Are the cyclists commuters taking a short cut? Or people using the park for exercise - just need to understand this? Secondly, is it the ladies defecating on the pitch or the pooches defecating?
Anyway, the steps required to solve include;
- Make a pest of yourself to the council. Report each and every incident (with picture evidence) to the dog warden, the litter warden, the park authorities. Get the direct email address of the relevant Director and send him a daily email with an update of offences on that day (with pictures, of the cyclists, the ladies and the poops).
- Get the community involved. Get your neighbours and other regular park users involved. Get the football club involved.
- Get onto local councillors. Make it clear that this is important to the community.
- Take citizens' action. For the cyclists, organise some nice picnics or sit-down protests right on their paths, so they have no choice but to go over grass or choose other routes. Put up obstructions (cones, barrells, tree trunks etc) to block their route temporarily. Take lots of pictures and videos. For the pooping pooches, start taking pictures of the ladies and the pooches. Explain to the ladies that you are publishing these photos on a name-and-shame website. Have a supply of nappy bags handy for when they tell you they have no bag with them. Drop flyers to local houses advertising this name-and-shame website.
- get the local papers involved, they will normally love this kind of thing, especially if you have pictures. They will be particularly keen on feedback from the football club.
Go back to the top and start again.