You can also use UW Libraries Search to find reports published by the City of Seattle and other local organizations. For example a 1974 study, Renovating decaying urban areas : an analysis of Seattle's Pioneer Square Historical district.
America History & Life is the best database to use when looking for academic journal articles in American & Canadian history.
Link your search terms using the AND connector. For example: seattle and urban renewal. On the search results screen, use the options on the left toolbar to narrow your search results. To find the fulltext of the article (if not provided directly in the database), click on the "Check for Full Text." Not all articles will be online, some may only be in print, others may not be available at the UW (you can request a pdf of these).
The raison d'être of historians is to explore the past and attempt to describe, explain, interpret and analyze it. Historians use evidence from the past (primary sources) to support their interpretations which are most often published in the form of books and journal articles (secondary sources). So why should you use secondary sources?
Keep in mind
How to Read Scholarly Books & Articles
Scholarly articles and books have a purpose -- an argument (also called a thesis) that they are attempting to make about an issue and present evidence to support this argument. As you read a scholarly article first check to see if there is an abstract, a brief overview of the article. This will give you an idea if the article will be relevant for your research. Then look for the author's argument. Ask yourself, does the author adequately support their argument with evidence.