# `make.lake`

[`make.lake`](#digger.make.lake) will modify an initial topobathymetric surface to add new water areas based on user-provided contours. This may be of use in areas that have bathymetric surveys in the form of contours. The following is typical usage for [`make.lake`](#digger.make.lake).

1. Prepare a topography file as a geotif.
2. Prepare or obtain a polyline shapefile that contains depth contours of the lake. Ensure that the geotif and shapefile have the same coordinate system.
3. Run [`make.lake`](#digger.make.lake) to generate input files for D-Claw. Inspect the output and adjust any input parameters as needed.
4. Using these files, set up a D-Claw simulation to run and analyze. `digger` will not do this for you.


A code snippet that uses [`make.lake`](#digger.make.lake) may be found in the file `digger/examples/pre-run/black_lake/make_lake_black_lake_example.py`. In this example, a DEM from the U.S. Geological Survey (2017) is adjusted to include depth data based on contours from Black Lake, Washington (Washington State Department of Ecology, 2022).

```{literalinclude} ../../../../../examples/pre-run/black_lake/make_lake_black_lake_example.py
:language: python
```

After this code runs, it will produce geotif and [topotype3](https://www.clawpack.org/topo.html) files that specify the modified topobathymetry.

It will also create diagnostic figures.

The standard diagnostic figure from [`make.lake`](#digger.make.lake)

```{figure} ../../../../_static/from_examples/black_lake.png
:alt: Example digger.make.lake summary figure.

An example of the diagnostic output provided by digger.make.lake.
```

A dictionary containing some diagnostic information is returned. It contains the following elements:

```{literalinclude} ../../../../_static/from_examples/black_lake_info.yaml
:language: yaml
```

Another example may be found in the file `digger/examples/pre-run/synthetic/make_lake_synthetic_example.py`. In this example, a synthetic lake is placed into flat topography.

```{literalinclude} ../../../../../examples/pre-run/synthetic/make_lake_synthetic_example.py
:language: python
```

In this example, we generated a lake from the following synthetic contour set:

```{figure} ../../../../_static/from_examples/herbie_contours.png
:alt: Contour set used by make.lake

The contour set used by make.lake
```

The standard diagnostic figure from [`make.lake`](#digger.make.lake)

```{figure} ../../../../_static/from_examples/lake_herbie.png
:alt: Example digger.make.lake summary figure.

An example of the diagnostic output provided by digger.make.lake.
```

A dictionary containing some diagnostic information is returned. It contains the following elements:

```{literalinclude} ../../../../_static/from_examples/lake_info.yaml
:language: yaml
```

**References**

Black Lake Bathymetry:
Washington State Department of Ecology, 2022, Lake Bathymetry Contour Lines, Accessed on September 4, 2025, at https://geo.wa.gov/datasets/waecy::lake-bathymetry-contour-lines/explore?location=46.316320%2C-124.040184%2C16.84.

Black Lake DEM
U.S. Geological Survey, 2017, USGS one meter WA Olympic Peninsula C2 2017, Accessed on September 4, 2025, at https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Elevation/1m/Projects/WA_Olympic_Peninsula_C2_2017/TIFF/.