Based on your data provided ...
Published by Zaid Rashdan, Principal environmental consultant at Al Masader Aldualiyah for environment and quality systems
Based on your data provided about the landuse within the catchment area, it's easier now too identify the parameters you have to measure, in this regard I would suggest the following :
Total pesticide (types determined based on quick survey with the agricultural sectors in the catchment area), total organic carbon, total hydrocarbons, heavy metals, pharmateculars, total nitrogen, ammonia, nitrate, fecal coliform and total coliform, acidity, bod5, cod, pesticides and fungicides
In case the purpose of infiltration or groundwater recharge, you have to identify the type of aquifers and its vulnerability , bed rocks and aquifers characteristics and it's chemistry