Are there any safe alternatives to Roundup?

We are planning to remove what is left of our almost dead (due to drought) lawn and have succulents and other water-wise plants put in instead.

We had a landscape designer come out to the house and have a consultation with us. We all decided on the types of plants we would like. She said that before the crew came out to remove the lawn, with some type of mechanical scraping device, we needed to kill the entire lawn with Roundup.

We’ve done some Research and have come to the conclusion that Roundup, and other similar products, are not safe for the environment. We won’t use it.

Does anyone know of any safe alternatives for killing the lawn, without adding carcinogenic agents to the soil or having those chemicals leech into the groundwater?