This book may be useful for you.

When that is one of the objectives of the university to contribute to the provision of water resources in the region  not to increase the demand . The campus rainwater will accumulate until the fall so you must be harvested and stored in large tanks where space reservoirs are determined based on the volume of water collection and the rate of rainfall areas or The mechanical methods can be used where the ground processing cleaned and then softening paved or covered metal or plastic plates, or possible use of impermeable areas or chemical methods also can be used by using chemicals to reduce the water permeability of the soil, such as sodium salts and paraffin wax. Finely the harvested water should be used for the use of multiple purposes such as irrigation of plants on campus, and to protect natural ecosystems and recreational facilities, and will be used for parks and green spaces that do not require additional water for irrigation coordinate methods, adding that the majority of plantings in the campus of the local species and adapted that do not require large amounts of irrigation water. Recycled water is also exploited in irrigation required to provide the needs of the treatment plant, and thus be part of the agenda of the university.

When you are designing a rainwater harvesting system. It is very important to consider the rainfall pattern, magnitude and its frequency. You need at least 30 years or more rainfall data to design such kind of system. Specially in my country (Sri Lanka) there are so many examples of failures due to insufficient rainfall to function the system. Please study more on rainfall pattern, first draw mass flow curve and intensity frequency curve to understand, how reliable your source(rainfall). For Sri Lanka we do not have our own guideline, but we use LEED New Construction Version 2.2 Reference Guide. It quite works well for tropical climate like Sri Lanka as well. Good Luck!

Hi Yeshwanth Babu Reddy, 

First you thoroughly analyze the college campus and collect the information regarding water flow of rainfall from the workers, sweepers and authorities.You have to harvest the rainfall from both building and ground. Connect all the sources of rainfall to the recommended feet in the ground.

This manual maybe helpful

First of you have to collect the rainfall data of your locality for last many year (preferably more than 30 years), analyse them probabilistically to get the most certain rainfalls (with 0.80 probability). Study the available open surfaces (land, rooftops, road surfaces etc.) and measure their areal extent. Other steps are given in  the paper by  Singh, V.K., Kumar, Anil and Santosh, D.T. (2011) "Planning and Design of Roofwater Harvesting System" International Journal of Agriculture, Environment and Biotechnology, Vol. 4(4) December: 375-381. Wish you happy reading. Thanks.

Thank you Mr. Anil for you'r inputs. And the paper did provide quite a few inputs.

https://www.researchgate.net/publication/321748624_A_PROJECT_REPORT_ON_DESIGN_OF_RAINWATER_HARVESTING_SYSTEM_FOR_LINGAYA'S_UNIVERSITY_CAMPUS

I hope this link will help you...