owllogovertThe Online Watershed Library (OWL) is a service provided by the Center for Watershed Protection that allows ready access to Center publications and other resources (research papers, tools, and stormwater manuals, among others) that support best practices in watershed and stormwater management. OWL is a searchable, online database of basic information, stormwater and watershed manuals and plans, assessment tools, regulatory information, and other watershed-related resources. Users may also submit materials for inclusion in the OWL.

OWL was developed to be a time-saver for watershed and stormwater practitioners as it provides users access to a well-organized database of relevant and up-to-date information. Due to copyright protection, not all publications included in OWL are available for download and in such circumstances, a link to the publication is provided.

Institutions or libraries that require a Licensing Agreement, click here.

 Browse Free
Center publications

All Center for Watershed Protection publications) can now be accessed using OWL. Electronic publications may be downloaded or order hard copies.

Attention: If you have downloaded free publications in the past, a login is no longer required. For access to the full Online Watershed Library(OWL), you can buy an annual subscription or join CWPA which includes a free annual subscription to OWL.

Click here to browse free Center publications.

Browse OWL

I’m a CWPA member

Begin your search now if you are a CWPA member with your login information.

Click here to login to the Member's Area and browse the complete Online Watershed Library (OWL).


Subscribe to OWL

I’m not a CWPA member

Non-CWPA members may purchase a subscription for $39.99/year to access the complete set of resources available in OWL.

Click here to register for an OWL subscription


Upload a document 

to be included in OWL

CWPA members or OWL subscribers may upload a publication

Click here to login to OWL and upload a document.




NEW! Read the July 2015 issue of the
Watershed Science Bulletin. Click Here!



The Mysterious Silt Influx of Hawkins Cove...




Zombie Invasion! When plants attack...

rsz 1rsz 1rsz japanese knotweed before treatment 2014-07-24



Read the March 2015 issue

of Runoff Rundown CLICK HERE!


Facts and Myths about Maryland's "Rain Tax" 

How much do you know about the stormwater fees and how they help protect our watersheds? Read the article and then check out our white paper:

The Value of Stormwater Fees in Maryland.



Need to develop an IDDE program?

Read the guidance.


Two versions of the Watershed Treatment Model (WTM) released to help users estimate benefits from a wide range of stormwater runoff and pollutant removal practices. Download your FREE COPY of the WTM and User's guide.