The New Jersey Hydrologic Modeling Database, or “H&H Database” as it has come to be known, is the culmination of several decades of data collection effort by NJ Soil Conservation Districts and the NJ Department of Agriculture (NJDA). Started in 1986 by Mr. Hunter K. Birckhead, P.E. (ret.) the NJDA Erosion Control Engineer, recognized the value of the hydrologic and hydraulic data being submitted to soil conservation districts for permit review by consulting engineers. Districts review and certify plans developed for erosion and sediment control under P.L. 1975, Chpt. 251, also known as the NJ Soil Erosion and Sediment Control Act (N.J.S.A. 4:24-39 et seq.). As part of this process, existing and proposed hydrologic and hydraulic site conditions are examined to ensure to the greatest extent practicable, that erosion during and after construction will be minimized. Mr. Birckhead instituted a statewide uniform data collection procedure to condense hydrologic data as well as stormwater management basin data onto summary forms along with copies of site plans and USGS quadrangle maps – the original “GIS”. The purpose was to use this data to create localized hydrologic models to improve the accuracy of permit evaluation for the prevention of offsite erosion, since assessing drainage designs without considering the local context of hydrologic and hydraulic conditions often causes permit reviewers and designers to operate in a kind of knowledge ‘vacuum’.

Since that time, NJ Soil Conservation Districts have collected thousands of summary forms containing land use and hydrologic design data for most of the development sites in New Jersey which were large enough to warrant the use of at least one stormwater basin. Site and basin design as well as land use and location data have been preserved for most of the development sites permitted by Districts since the mid 1980’s. Because of limitations in technology at that time, the data were used only on a limited basis. However, Districts continued to collect new data as it became available through the permitting process.

In 2007, The Department began the development of an electronic, web-based database that could warehouse all this data, and make it available to professionals involved in land use development and planning. With several grants from the New Jersey Department of Environmental Protection, NJDA sought the assistance of Rutgers University in the development of an initial prototype database as well as the current version which you see here. In addition to the storage and retrieval of design data, the Database can also store images of site plans (where available), photos of current basin conditions and even written documents such as operation and maintenance plans. The database can also record maintenance inspection records for individual basins (a future project being developed by NJDA, NJDEP and Conservation Districts).

The data contained in the database were originally submitted to NJ soil conservation districts as part of the permit review process and are part of the public record. While every effort has been made to review the data for accuracy and correctness, the final responsibility for accuracy rests with the original designer(s). Site plans and design data are subject to all applicable copy write and intellectual property rights laws.

The Department of Agriculture with NJ Soil Conservation Districts and the New Jersey Department of Environmental Protection seeks to continually improve the data quality and utility of the database. Comments, corrections and suggestions are welcome.