---
title: how to build a natural asset inventory with the staff you have
canonical_url: https://ensurance.app/guide/how-to-build-a-natural-asset-inventory
markdown_url: https://ensurance.app/guide/how-to-build-a-natural-asset-inventory.md
subtitle: "six steps, most of them with maps you already hold, for a team of one"
category: how-to
---

# how to build a natural asset inventory with the staff you have

*six steps, most of them with maps you already hold, for a team of one*

A **natural asset inventory** is a list of the living ground a city or town depends on, with enough detail about each piece to manage it: where it is, how big it is, what condition it is in, what it does, what threatens it, and who relies on it. It is the first step in natural asset management and the input every valuation needs. You can build a useful first version with the staff you already have.

This guide is written for a team of one. That might be the sustainability coordinator in a town that signed the Global Covenant of Mayors, or the analyst in a C40 city's climate office who was handed "nature" as a fifth priority. The steps are the same at both scales. A metro has more rows.

The creek, the wetland, the woodlot and the canopy are already doing their work, listed or not. A list does not protect them, and it is not their worth. It makes them visible to the people who decide what gets maintained, and that is where protection starts.

:::johnson
**you cannot manage what you have not listed.**

Six steps, most of them using data you already hold. The list is yours whether or not you ever hire anyone to value it.

[see the flows a list can name →](/natural-capital/flows?from=guide)
:::

## why start with the inventory

Every later step depends on it. A valuation needs acres and condition. A risk assessment needs to know which ground holds the hazard back. A funding ask needs to name the asset and the people who benefit. If the list is wrong, everything built on it is wrong.

The Municipal Natural Assets Initiative in Canada works in that order. Its Inventory Acceleration project helped 31 local governments take stock of their natural assets. Each received the inventory as a table and a dashboard, plus a summary report. MNAI's method runs identify, then value, then account, and its published guidance is worth reading before you start. That sequence, list first and value second, is a good one to copy.

## step 1: decide what counts

Start with a working definition: **a natural asset is living ground that delivers a service the city would otherwise build, buy or go without.** Then list the services you care about most this year. For most cities that is stormwater and flood, heat, drinking water, and air. For a coastal town, add storm surge. For a town on a single aquifer, put groundwater first.

Do not try to inventory everything green. A median strip of turf grass is green. It is not usually an asset in this sense.

## step 2: pull the maps you already have

You probably hold more than you think:

| source | what it gives you | who usually has it |
|---|---|---|
| Land cover data (national or regional) | Forest, wetland, grassland, developed land, by area | Planning or GIS |
| Wetland and stream maps (in the US, the National Wetlands Inventory; in Canada, the Canadian Wetland Inventory) | Where the water sits and moves | Environmental or public works |
| Floodplain maps | Where flooding reaches | Emergency management or planning |
| Tree canopy assessment (an i-Tree study, if you have one) | Canopy cover by block or ward | Forestry or parks |
| Parks and open space register | Publicly owned green space | Parks |
| Parcel and ownership data | Who owns each piece | Assessor |
| Source water protection areas | Ground that feeds the drinking supply | Water utility |

Overlay them. Every distinct patch of forest, wetland, stream corridor, floodplain, park and canopy becomes a row.

## step 3: record extent and ownership

For each row: what type of ground it is, how many acres, and who owns it. Ownership matters more than most inventories admit. A wetland on city land can be managed this year. A wetland on private land needs a partner. A forest outside the city limits that feeds the reservoir needs a neighbor. Note all three. The last group is often the most important, and step 6 comes back to it. Note too where the ground is held under Indigenous title, treaty or customary rights. The holder is a partner in any plan for it, not a row to be valued.

## step 4: rate condition, roughly

Condition is where inventories stall, because a full ecological survey is expensive. Do not let it stop you. Use a three-point scale (good, fair, poor) and say what you based it on: a site visit, aerial imagery, a recent report, staff knowledge. A rough rating with a stated basis is more useful than a blank column.

Condition matters because a degraded wetland does less work than a healthy one. A valuation will adjust for it. A management plan will act on it. If your asset management team already rates pipes by condition and risk of failure, use their scale, so the rows can sit in the same register.

## step 5: write down what each asset does

For each row, list the two or three services it provides that you care about. The floodplain park stores stormwater and cools the neighborhood. The forested ridge keeps sediment out of the reservoir. The canopy on the east side shades the blocks with the most heat illness.

Use plain words. You do not need a classification system to start. When you hand the list to a valuation, the services get matched to published per-acre values. Our engine uses a fixed vocabulary of ecosystem types and flows, which you can see on [the natural capital page](/natural-capital/flows?from=guide), but your list does not have to.

## step 6: write down who depends on it, both ways

This is the step most inventories leave out, and it is the one that makes funding possible. For each asset, ask two questions.

**Who downstream depends on this ground?** The homes below the floodplain, the hospital whose basement floods, the utility whose intake sits below the forest, the school on the hot block.

**What does this ground depend on?** The upstream forest that feeds the stream, the neighboring wetland that shares the water, the habitat corridor that keeps the species moving.

The answers to the first question are your potential funders. The answers to the second are the assets you may not own but cannot afford to lose. [Your city is upstream and downstream at once](/guide/your-city-is-upstream-and-downstream-at-once?from=guide) explains why both directions matter.

## what to do with the list

A finished first inventory is a table, one row per asset. Its length depends on the ground, not the size of the staff. With it, you can:

- **Bring it to the next capital plan.** When a stormwater or flood project is costed, the asset that does the same job can be costed beside it.
- **Add it to the risk assessment.** Each hazard now points to the ground that holds it back. [A risk assessment is a list of parcels](/guide/a-risk-assessment-is-a-list-of-parcels?from=guide) shows how.
- **Value it.** Hand the list to a valuation and get back what each asset does in a year, what it would cost to secure, and who depends on it. [Why a city should run an ecosystem service valuation](/guide/why-a-city-should-run-an-ecosystem-service-valuation?from=guide) covers what that number is good for.
- **Share it with your region.** A town is usually smaller than its watershed. The neighbor upstream has the other half of the list.

## common mistakes

**Waiting for perfect data.** Start rough. A list with stated assumptions can be improved. A list that does not exist cannot.

**Only listing what the city owns.** The forest that feeds the reservoir is often outside city limits. Leave it out and the inventory misses the asset with the most at stake.

**Treating every patch the same.** A wetland that sits above a hospital matters more to the city than one of the same size in an empty field. Note the dependents and the priority follows.

**Stopping at the inventory.** A list in a drawer is a report. A list in the capital plan is management.

## frequently asked questions

### what is a natural asset inventory?

It is a list of the natural features a local government depends on for services, such as wetlands, creeks, forests, aquifers, parks and urban canopy. Each entry records where the asset is, how big it is, who owns it, its condition, what it does, and who relies on it.

### how long does a first inventory take?

It depends mostly on how much mapping you already hold and how many departments you have to ask. A small town with land cover, floodplain and parcel data in hand is assembling, not surveying. A metro takes longer because there are more assets and more owners, not because the method is harder.

### do we need GIS staff?

It helps, but it is not required to start. A list built from existing maps and staff knowledge is a legitimate first version. GIS makes the second version better.

### what comes after the inventory?

Valuation, then a management plan, then funding. Each step uses the one before it.

## next steps

Pick your two most important services and pull the maps for them this week. Build the first twenty rows. When you want the numbers, the regional natural asset analysis on [our services page](/services?from=guide#finance) values every asset on the list together. If you work for a regional covenant or a city network, [we can talk about a cohort](/contact?from=guide&topic=city-nature-valuation) so towns use one method.

## sources

- [Water Canada, "MNAI project to help 30+ communities reduce costs, adapt to climate change"](https://www.watercanada.net/mnai-project-to-help-30-communities-reduce-costs-adapt-to-climate-change/): Inventory Acceleration project
- [Greenbelt Foundation on the MNAI inventory project](https://greenbelt.ca/?p=6374): participants and deliverables
- [Smart Prosperity Institute, MNAI cohort summary](https://institute.smartprosperity.ca/sites/default/files/mnai-cohortsummary.pdf): methodology for identifying, valuing and accounting for natural assets

## the series

1. [how a city values the nature it already owns](/guide/how-a-city-values-the-nature-it-already-owns?from=guide)
2. [why a city should run an ecosystem service valuation](/guide/why-a-city-should-run-an-ecosystem-service-valuation?from=guide)
3. **how to build a natural asset inventory with the staff you have** (you are here)
4. [what a city's green space is worth, and what the number is for](/guide/what-a-citys-green-space-is-worth?from=guide)
5. [price what the creek already does](/guide/price-what-the-creek-already-does?from=guide)
6. [your city is upstream and downstream at once](/guide/your-city-is-upstream-and-downstream-at-once?from=guide)
7. [hire a natural asset valuation for your city or town](/guide/hire-a-natural-asset-valuation-for-your-city?from=guide)