The Net Anthropogenic Nitrogen Inputs (NANI) and Phosphorus Inputs (NAPI) Toolboxes


With funding from the NOAA Coastal Hypoxia Research Program (CHRP), we have developed a set of tools, the NANI calculator toolbox, which allows the user to calculate NANI (Net Anthropogenic Nitrogen Inputs; Howarth et al. 1996; Boyer et al. 2002) from commonly available databases downloadable from the Internet. The corresponding toolbox for calculating phosphorus inputs (NAPI) is also available. The toolboxes comprise a set of tools that:

  1. 1) Calculate the proportions of various political boundaries falling into watersheds (“NANI-GIS tools”),
  2. 2) Extract and organize relevant data downloaded from web-based datasets to be used by the budgeting tool (“NANI- or NAPI-extraction tools”), and
  3. 3) Calculate the components of NANI or NAPI and other relevant items possibly used for other purposes, for example relevant inputs to ReNuMa (“NANI- or NAPI-budgeting tools”).

The toolbox is designed so that the only input the user needs to provide is a map of watershed(s) of interest.  Other inputs, such as agricultural census data, are either included in the toolbox package or are readily available on the Internet.  The versions of the tools shown here are designed for US datasets only, because they rely on US datasets (see NANI toolbox documentation). A version suitable for use in EU countries that has been developed for assessing NANI in the Baltic watershed is available at:

The NANI toolbox documentation describes how each of the tools in the toolbox works, using the NANI calculation of US watersheds as an example.  Figure 1 below shows the data flow of the NANI and NAPI toolbox calculations.  Note that the specific calculations may be altered depending on the availability of datasets.  For example, in this example the watershed population is estimated based on the county level census data.  If desired, however, the same calculation can be done at the census block level using appropriate data.

NANI and NAPI toolbox components can be downloaded from the links below. The components are updated from time to time, so check back for the latest version.

Figure 1. Overview of NANI and NAPI calculator toolboxes applied to US watersheds.

For more information, contact:

NANI/NAPI Toolbox documentation, V3.1 (PDF)

NANI Toolbox documentation, V3 (PDF)

NANI GIS Tools (zipped format, ~9 Mb)


NANI Accounting Tool,V3.1.0 (Excel worksheet ~141 Mb)

NANI Accounting Tool,V3 (Static, Excel worksheet ~17.3 Mb)

Notes on NANI Accounting Tool,V3.0.1 (Word document, ~31 Kb)


NAPI Accounting Tool,V3.1.0 (Excel worksheet ~151 Mb)

Notes on NAPI Accounting Tool,V3.1 (Word document, ~25 Kb)


NANI Extraction Tool V3.1 – Ag Census Animals 12_07 (~222Mb)

NANI Extraction Tool V3.1 – Ag Census Crops 12_07 (~221Mb)

NANI Extraction Tool V3.1 – CMAQ N deposition Estimates (Excel Worksheet, ~27.3 Mb)

NANI Extraction Tool V3.1 – US Census (Excel Worksheet, ~30.6 Mb)


NANI Extraction tool, V3 – Ag Census, Crops, 1987-97 (Zipped format, ~107Mb)

NANI Extraction tool, V3 – Ag Census, Crops, 2002-07 (Zipped format, ~182 Mb)

NANI Extraction tool, V3 – Ag Census, Animals, 1987-97 (Zipped format, ~107Mb)

NANI Extraction tool, V3 – Ag Census, Animals, 2002-07 (Zipped format, ~183 Mb)

NANI Extraction tool, V3 – US Census (Zipped format, ~3.7 Mb)

NANI Extraction tool, V3 – USGS Nutrient Input Estimates (Zipped format, ~4.7 Mb)

NANI Extraction tool, V3 – CMAQ N deposition Estimates (Zipped format, ~11.1 Mb)


NAPI Extraction tool, V3.1.0 – Fertilizer (Zipped format, ~10 Mb)





Previous Versions of the toolbox

Support for development of the NANI Toolbox has been provided by:

noaa_logo nccos USDA Logo

Work has been supported by NOAA award NA05NOS478120 from the NOAA Center for Sponsored Coastal Ocean Research, Coastal Hypoxia Research Program, to D. Scavia, G. Helfand, R. Howarth, R. Alexander and D. Breitberg.