Step-by-Step Tool Selection

PREFACE

This guide was developed to help water fund developers and practitioners select the right tool(s) for answering key questions in the Feasibility or Design Phases of a Water Funds Project Cycle. Ideally as you develop a Water Fund you will be seeking the advice of a wide variety of experts, including those with technical expertise in hydrology or water resource management. These experts will be able to provide further guidance on the selection of appropriate tools.

STEP 1. Determine the questions you need answered. 

The purpose of the ecosystem services modeling is important, as it will determine which the complexity of data, model type and analysis needed. Funds may wish to answer different questions depending on which phase in the project cycle you are in; for example, feasibility studies may focus on quantifying the maximum potential for nature-based solutions, while project design studies may focus on which activities and where to implement them. Example water fund questions that models can help answer:

• Can land management make a difference in the challenges that we’re facing? What is the maximum impact that we can achieve with nature-based solutions in our project area?
• Where are the ecosystem services provided and where are they threatened?
• If I have $X to spend, what is the economic benefit to communities both upstream and downstream?
• If I have $X to spend, where and what activities should I do to have the most impact?

STEP 2. Identify which ecosystem services you will model.

These can include, for example:

• Water purification / filtration (for non-point pollutants such as nitrogen and phosphorus)
• Sediment retention / soil conservation
• Water regulation (base flow, seasonal flows or flooding)
• Groundwater storage
• Carbon sequestration and storage
• Recreation and tourism

STEP 3. Recognize the main audience(s) for your model results. 

This sets burden of proof, level of complexity required, and the types of outputs that you will need to produce from the modeling study. Take time to think through how you plan to talk about your results and the story that your modeling study will inform.

STEP 4. Identify any existing models that could be applied to address the key questions. 

Check on their relevance, last date updated, and whether they are already used in official processes or part of the local dialogue. If there is an appropriate existing model, consider using this for water fund analyses.

STEP 5. Consider the spatial extent of the modeled area 

Specifically, how large does the modeled watershed or region need to be to answer your key questions?

STEP 6. Consider the local data availability. 

Do you have input data available to use in the model or are you looking for models that require only easily-available, global data?

STEP 7. Identify models that fit the needs of the project (see Table below).

STEP 8. Review model requirements and application context to determine fit of model for purpose. 

Match to capacity of project. Ask questions such as: Who will run the model and what is their level of expertise? What resources are available (in-house or $ to hire)? How will we share the results?.

STEP 9. Create study design. 

Establish how you will use the outputs of the selected model(s) to answer the key questions and how you might use the output of one model as the input for a follow-up analysis. For example, you may need to adjust outputs from a hydrologic model (like InVEST or SWAT) to use as input for ROI or Cost-Benefit calculations. Also consider how you may use the models throughout the project cycle, such as for adaptive management once work is happening on the ground and / or you have monitoring results that you can use to calibrate and improve the model setup.

STEP 10. Select model(s), collect and prepare input data, run model(s), calibrate and document your work.