Question: Of what valley is the birthplace of Brent Livermore the commercial hub?

Context paragraphs:
Tikkurila: Tikkurila (Swedish: "Dickursby" ) is a district and major region of the municipality of Vantaa, Finland.  Located in the eastern half of the Helsinki conurbation, some 16 km north of the capital's downtown district, it is the administrative and commercial hub of Vantaa, although Myyrmäki is a rival commercial hub within the municipality.

Indore–Pune Express (via Panvel): The Indore–Pune Express is a Mail/Express Train of the Indian Railways, which runs between Indore Junction railway station railway station of Indore, the largest city and commercial hub of Central Indian state Madhya Pradesh and Pune Junction railway station of Pune, the commercial hub of neighbouring state Maharashtra.  It is the second rail connection between Indore and Pune other being Indore–Pune Express.  This is first train from Indore to Navi Mumbai.

Grafton, New South Wales: The city of Grafton is the seat of Local Government, the Federal and State Government administrative centre, and the commercial hub of the Clarence River Valley.  Established in 1851, Grafton features many historic buildings and tree-lined streets.  It is located approximately 630 kilometres north of the New South Wales State capital, Sydney, 340 km south of Brisbane, Queensland and approximately 35 km west of the Tasman Sea coast.  As at June 2015, Grafton had a population of 18,689.

Livermore Valley AVA: The Livermore Valley AVA is an American Viticultural Area in Alameda County, California, surrounding the city of Livermore in the Tri-Valley region.  Both the AVA and the city are named after Robert Livermore, a landowner whose holdings encompassed the valley.  The groundwater basin underlying the valley is the Livermore Basin, the largest sub-unit of which is the Mocho Subbasin.  The Livermore Basin is one of five aquifers in the San Francisco Bay Area that supply most of the metropolitan Bay Area population.  The entire Livermore Basin aquifer faces a concern over elevated total dissolved solids by the year 2020 due to an expanding human population leading to higher rates of return water flows to the aquifer containing certain salts.

Chennai Cheetahs: Chennai Cheetahs (CCH) is a field hockey team based in Chennai, Tamil Nadu, India, that plays in World Series Hockey.  It is owned by Chennai Sports Organisers Private Limited (CSO).  The team is captained by the Australian Brent Livermore and coached by the Spaniard Jose Brasa.  The team's home ground is the Mayor Radhakrishnan Stadium.

Gordon-North Sydney Hockey Club: Gordon North Sydney Hockey Club, often called GNS, is a hockey club based on the North Shore of Sydney, Australia.  The Men's team includes Australian reps Brent Livermore, Jamie Dwyer and Mark Knowles.

Eden Valley, New Zealand: Eden Valley is an inner-city suburb of Auckland, the largest and most populous urban area in New Zealand.  The suburb grew around Dominion Road, one of the Auckland’s main arterial routes.  Eden Valley's commercial hub is made up of a collection of businesses, shops, and dining options that service the area.  The eclectic collection of shop fronts and signage on Dominion Road has aptly been described as, "colour and chaos".  The "colour and chaos" of the commercial hub is strongly contrasted by the surrounding residential area.  Eden Valley is characterized by heritage buildings that house modern day businesses, a residential area that has a range of late Victorian, Edwardian and transitional bay villas, and basalt and scoria stone walls that give the area a long established feel.

Brent Livermore: Brent James Livermore OAM (born 5 July 1976 in Grafton, New South Wales) is a field hockey midfielder from Australia.  He was first selected in the Australian team in 1997, and was awarded the Kookaburras player of the year award in 2001.  He was also nominated of the FIH player of the year awards in 2002 and 2005.  He has played over 300 matches for the Australian team, and has scored 30 international goals.  He plays for the NSW Waratahs in the Australian Hockey League.

Bernal Subbasin: The Bernal Subbasin is an aquifer located in the southwestern corner of Livermore Valley Groundwater Basin, Alameda County, California, United States.  All of the groundwater in Livermore Valley moves toward the Bernal Subbasin, which is bounded on the east by Pleasanton Fault, on the north by the Park Fault, and on the west by the Calaveras Fault. (Earth Metrics, 1989) All the streams draining the Livermore Valley merge above the Bernal formation and exit this subbasin and Livermore Amador Valley via the Arroyo de la Laguna.

Shipra Express: The Shipra Express (Hindi: इंदौर - हावड़ा क्षिप्रा एक्सप्रेस Bengali: ইন্দোরে - হাওড়া শিপ্রা এক্সপ্রেস, Urdu:حافظة شبرا إكسبرس - اندر) (pronounced as Shiprã Express) is a tri-weekly super fast express train of Indian Railways, which runs between Indore Junction railway station of Indore, the largest city & commercial hub of Central Indian state Madhya Pradesh and Howrah, the commercial hub of Kolkata.  The name 'Kshipra' signifies the Shipra River, one of the holiest river of Hindus near Ujjain City.

Supporting paragraphs: Brent Livermore Grafton, New South Wales
Answer: Clarence River Valley