By default maven puts all of the jar files corresponding to the dependencies it downloads into ~/.maven directory. You can change this default behavior by creating a ~/build.properties file and including a definition of maven.home.local (see http://maven.apache.org/reference/properties.html
)
In addition the lcsim tests download data files needed for testing. These are stored in ~/.cache by default. The root of the cache directory can be controlled by setting the property org.lcsim.cacheDir.
So an example of a suitable ~/.maven directory would be
~/build.properties
maven.home.local=/scratch/.maven org.lcsim.cacheDir=/scratch/.lcsim